Technical Sessions

The following 52 sessions were planned for the SSA 2017 Annual Meeting in Denver.

Advances in Earthquake Early Warning

Earthquake early warning (EEW) systems provide advance warning of potentially damaging ground shaking and enable the activation of protective actions to prevent or reduce injuries or economic losses. A variety of EEW alert capabilities are in operation or under development in multiple regions of high seismic risk around the world. These vary in complexity from systems that take relatively simple actions based on ground motions exceeding a threshold at a single site to network-based systems that track an evolving rupture across multiple sensors. All EEW systems must consider: 1) types and quality of available ground motion data (seismic, GNSS, etc.), 2) sensor layout including station distribution, telemetry, and latencies, 3) methodologies for estimating source properties and/or predicting ground motion, 4) communication and use of alerts, and 5) evaluation of system performance. We invite contributions that address all aspects of EEW systems from the theoretical underpinnings to education and outreach efforts.

Session Chairs
Elizabeth Cochran <>

Angela Chung <>

Douglas Given <>


Advances in Seismic Full Waveform Modeling, Inversion and Their Applications

3D full waveform modeling and inversion holds promise for more accurate account of wave propagation, higher resolution Earth models, and better earthquake location and characterization. This session includes, but is not limited to, development and verification of full waveform forward modeling methods, and novel inverse algorithms, together with their applications in accurate source location (Earthquakes or Nuclear tests), imaging of velocity and attenuation structure at local to global scales, as well as full waveform migration. Topics related to quantitative interpretation of tomographic models (using seismological, geological or geochemical data) are also welcome.

Session Chairs
Nian Wang <>

Xueyang Bao <>

Dmitry Borisov <>

Youyi Ruan <youyir@exchange.Princeton.EDU>


Assessment and Management of Hazards from Seismicity Induced by Hydraulic Fracturing

There has been growing recognition of the potential for hydraulic fracturing to induce significant (M>3) earthquakes in a small percentage of horizontal well completions. Assessment and mitigation of potential hazards from this seismicity poses unique challenges due to the highly clustered nature of the activity in time and space, and the difficulty of predicting in advance whether such activity will occur. It is also not clear what mitigation measures might be effective, once a sequence has been initiated. We invite papers dealing with all aspects of this particular problem, including earthquake nucleation processes, assessment and characterization of sequences and their likelihood, regional variability of susceptibility, ground motions generated by sequences, traffic light protocols, and hazard assessment and mitigation.

Session Chairs
Gail Atkinson <>

David Eaton <>

Ryan Schultz <>

Honn Kao <>


Characterization of the Stress Field and Focal Mechanisms for Earthquake Source Physics and Fault Mechanics

Accurate estimation of the state of stress and pore fluid pressure is important for understanding processes leading to fault reactivation and earthquake nucleation. The main purpose of this session is to foster communication between researchers from different fields focussing on characterization of the stress field at global, regional (e.g. near large tectonic structures or subduction zones) and local scale (e.g. in relation to man-made perturbations). Of particular interest is the link between stress-field and pore pressure estimations from seismology and state-of the art modelling approaches. Contributions may regard (but are not limited to) studies of:

  • New techniques to improve characterization of stress field orientation, stress magnitudes and pore pressure, or comparisons of existing techniques.
  • Structural, tectonic or dynamic factors perturbing the stress field (e.g. large magnitude earthquakes, anthropogenic activities, temperature changes, aftershock/foreshock sequences, fault bends), implications of these perturbations and their spatio-temporal extent.
  • Analysis of earthquake moment tensors: relation with the stress field and implications for earthquake source physics.
  • Orientation, consistency and associated seismic hazard of fault structures with respect to the local/regional stress field. Implications for the frictional properties of faults and/or formation and growth of faults.
  • Stress heterogeneity at different scales and potential relation with varying earthquake source physics (e.g. stress drop, b-value).
  • The role of the background stress field and pore pressure for earthquake triggering via stress redistribution.

Session Chairs
Patricia Martínez-Garzón <>

Jeanne L. Hardebeck <>

Martha Savage <>

Marco Bohnhoff <>


Closing the Gap between Laboratory-based Damping Models and Observed Attenuation of Seismic Waves in the Field

Seismic wave attenuation is an important topic for both, seismology and engineering. It plays a key role in the prediction of ground motions, the estimation of site effects and the evaluation of seismic hazards. The seismic quality factor, Q, is a dimensionless quantity that is inversely proportional to the attenuation of elastic wave energy, and it is widely used in engineering seismology. Damping ratio, ξ, is used to quantify energy dissipation in geotechnical engineering and it is obtained through laboratory experiments that primarily measure hysteresis. Dynamic testing of small-scale soil samples can only characterize material damping and fails to capture other mechanisms of attenuation as they occur in the field (e.g. scattering). However, laboratory-based damping ratio curves are typically used with no modification for differences between the laboratory and field conditions. The high-frequency spectral decay parameter, κ, is based on characteristics of low-intensity ground motions recorded directly in the field, which makes it an observable parameter that quantifies total path attenuation. The main purpose of this session is to bring together researchers focused on the characterization of damping from different perspectives in an attempt to improve our ability to constrain this elusive parameter. Contributions may regard (but are not limited to) studies of: 1) quantification of the attenuation of seismic waves from field, laboratory, and numerical studies; 2) comparisons of material damping values determined through different approaches; 3) innovative methodologies for quantifying anelastic attenuation, 4) methodologies for harnessing data from field and laboratory studies, and 5) implications of attenuation and its associated uncertainty in site response analysis and site-specific seismic hazard assessment.

Session Chairs
Albert Kottke <>

Ashly Cabas <>

Computational Infrastructure and Data for Enhancing Earthquake Science
Advances in earthquake science are becoming increasingly tied to advances in computational infrastructure. Because earthquake processes span multiple spatial and temporal scales, ranging from microscopic, millisecond source physics to long-term, global tectonic scales, earthquake scientists must rely on computational laboratories to integrate disparate data sets and perform simulation experiments. This session focuses on advances in computational infrastructure and data synthesis for enhancing earthquake science, including software, supercomputing, simulation models, sensor technology, heterogeneous data sets, cloud computing, management of huge data volumes, and development of community standards.

Session Chairs
Lisa Grant Ludwig <>

Andrea Donnellan <>

Earthquake Complexities Revealed by Kinematic and Dynamic Modeling and Multiple Geophysical Data Sets

In recent years, spatiotemporal and geometrical earthquake rupture complexities have been imaged with increasing detail. In particular, large to great earthquakes (M > 7) often show segmented rupture, involve multiple faults, and trigger large nearby aftershocks almost instantaneously. The complexity of large earthquakes challenges traditional source imaging approaches and motivates developments of novel methods to map the space-time evolution of the rupture process. The use of multiple data sets, such as seismic, geodetic and tsunami measurements, opens an avenue for future improvements in kinematic source modeling, but requires new statistical means to optimally weight individual data sets. Similarly, appropriately quantifying the uncertainties of the resulting source models is needed to assess which parts of the rupture process are well imaged. At the same time, incorporating local geology, regional tectonics and principles of earthquake dynamics is very valuable to understand and interpret the observed rupture pattern. This session discusses new approaches, new data sets, and latest findings in kinematic source imaging and dynamic rupture modeling. We invite contributions related to kinematic source imaging with new methods, improved uncertainty quantification, and using multiple data sets. In particular, we solicit studies that provide unified interpretations of observed kinematic rupture patterns with earthquakes dynamics, as well as post- and inter-seismic processes and the local tectonic framework. We also solicit contributions on dynamic rupture simulations on geometrically complex faults, and studies that incorporate new rupture physics and laboratory rupture experiments that are reconciled with geophysical observations.

Session Chairs
Wenyuan Fan <>

P. Martin Mai <>

David D. Oglesby <>


Earthquake Geology and Paleoseismic Studies of the Intermountain West: New Methods and Findings on Seismic Hazard Characterization of Low Slip Rate Faults

The intermountain west is a broad region characterized by distributed faulting with relatively low slip rates and long recurrence intervals. These factors create a unique set of challenges for geologists and seismologists tasked with understanding the seismic hazard of the region. Despite these difficulties, scientists are developing innovative methods to characterize faults, assess seismic activity, and place constraints on contemporary deformation of the intermountain west; these studies are progressing the methodologies for evaluation of seismic hazard, and improving informed decision making by regulatory and planning agencies. We invite studies from researchers and practitioners presenting new results of this nature within the intermountain west region including, but not limited to, the Walker Lane, Basin and Range, and the Rio Grande Rift. Particular topics of interest include: 1) paleoseismic estimates of earthquake recurrence, magnitude, slip rate, and rupture extent; 2) application of high resolution topography; 3) objective techniques for evaluating paleoseismic data quality and synthesizing datasets; 4) integration of geologic and geodetic data; and 5) techniques for evaluating fault segmentation and multi-fault rupture.

Session Chairs
Seth Dee <>

Stephen Angster <>


Earthquake Impacts on the Natural and Built Environment

In this session, we invite presentations on earthquake effects and their impacts. This includes models of landslides, liquefaction, lateral spreading, surface fault rupture, building damage, and infrastructure/lifeline performance, as well as broader multi-hazard impact analyses. We encourage submissions on empirical and analytical models, sensitivity analyses, data analyses, and scenario exercises. Given the challenges of linking secondary effects and their impacts to simplified shaking parameters, we also encourage submissions on innovative parameterizations of ground motion shaking intensity to account for cumulative energy, frequency content, and duration effects. Similarly, we hope to include recent developments on proxies for predicting the likelihood and the spatial distribution of earthquake ground failure impacts.

Session Chairs
Eric Thompson <>

Kate Allstadt <>

Kishor Jaiswal <>

Nilesh Shome <>


Earthquake Interaction and Triggering: From Near Field to Far Field, From Natural to Induced

Unraveling patterns and mechanisms of earthquake triggering is important for understanding earthquake occurrence and seismic hazard forecast. For example, aftershocks are consequences of static and/or dynamic stress perturbations from mainshocks. Whereas static-stress triggering is most effective at near field, dynamic-stress triggering has been widely reported to cause earthquakes and nonvolcanic tremor remotely. Recent studies show dynamic triggering is common in the near-to-intermediate field, and capable to cause damaging earthquakes. Faults near oil-and-gas and geothermal fields are also highly susceptive to dynamic triggering. Such observations lead to questions regarding fault friction properties, tectonic stress conditions, and fault hydraulic responses. This session discusses new observations and models related to earthquake interaction and triggering. We invite contributions from studies of near-field to remote earthquake triggering and studies of natural and anthropogenically induced earthquake interactions. We also solicit research of hydro-mechanical modeling and dynamic simulations of fault interactions, which incorporate laboratory experiments and field observations.

Session Chairs
Wenyuan Fan <>

Andy Barbour <>

Xiaowei Chen <>


Earthquake Rapid Response

Rapid deployments of seismic arrays and GPS receivers after recent large earthquakes demonstrate the power of well recorded aftershock sequences and the postseismic deformation field to shed light on earthquake ruptures and transient processes associated with these events. In the wake of large earthquakes, coordinated, dense, well positioned deployments of seismic arrays, GPS receivers, and EM/MT instruments, combined with field studies and satellite based geodetic measurements and imagery, provide a high-resolution definition of the rupture zone, rupture-limiting structures, and insight into postseismic deformation, earthquake triggering, the role of fluids in faulting, changes in material properties, and fault zone healing. Data from earthquake rapid response efforts can advance earthquake forecasting research and yields a densely sampled high-resolution data set to characterize in detail earth structure and to image fault networks.

We invite abstracts that report results from post earthquake response efforts and aftershock studies, address the benefits of multidisciplinary data collected after an event, present ideas about how to better coordinate efforts and improve efficiencies of rapid deployments, and technological developments that enhance our ability to effectively deploy instruments and/or collect field data after large events.

Session Chairs
Anne Meltzer <>

Jay Pulliam <>

Dan McNamara <>


Earthquake Source Parameters: Theory, Observations and Interpretations

Understanding origin and spatio-temporal evolution of seismicity needs a careful quantitative analysis of earthquake source parameters for large sets of earthquakes in studied seismic sequences. Determining focal mechanisms, seismic moment tensors, static stress drop, apparent stress and other earthquake source parameters provides an insight into tectonic stress and crustal strength in the area under study, material properties and prevailing fracturing mode (shear/tensile) in the focal zone, and allows investigating earthquake source processes in greater details. In addition, studying relations between static and dynamic source parameters and earthquake size is essential to understand the self-similarity of rupture process and scaling laws and to improve our knowledge on ground motion prediction equations.

This session focuses on methodological as well as observational aspects of earthquake source parameters of natural or induced earthquakes in broad range of magnitudes from large to small earthquakes, including acoustic emissions in laboratory experiments. Presentations of new approaches of focal mechanisms determination, seismic moment tensors and other source parameters as well as case studies related to analysis of earthquake source parameters are welcome. We also invite contributions related to scaling of static and dynamic source parameters and to self-similarity of earthquakes.

Session Chairs
Vaclav Vavrycuk <>

Grzegorz Kwiatek <>

German Prieto <>


Earthquakes and Tsunamis

This general session brings together a collection of presentations with the common theme of Earthquakes and Tsunamis.

Session Chairs
Rich Briggs

Gavin Hayes <>


Emerging Opportunities in Planetary Seismology

In the coming years and decades NASA may launch missions to explore Mars, our Moon, and the Ocean Worlds of the Solar System (e.g., Europa and Enceladus, and Titan). The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission that will lend on Mars in November 2018 will be the first Mars lander to place an ultra-sensitive broadband seismometer on the planet’s surface. The Lunar Geophysical Network, identified as a high-priority New Frontiers class mission in the Planetary Science Decadal survey, seeks to understand the nature and evolution of the lunar interior from the crust to the core. In addition, concepts are being developed to explore the interior of Venus, asteroids and comets.

The objectives of these missions vary. While InSight and the Lunar Geophysical Network are primarily geophysical missions, missions to our Ocean Worlds focus the detection of life and conditions for life. Despite these differing emphases, mapping the shallow and deep interior of planetary bodies is essential, as their interiors hold the clues for understanding their planetary evolution as well as for determining their thermal and chemical make-up and thus their habitability. The tool that can most efficiently reveal the detailed structures of planetary interiors is seismology.

This session invites presentations on seismological exploration of planetary interiors. Authors are invited to present re-analysis of data from past missions (Apollo and Viking) and from terrestrial analogs, as well as concepts, models, and simulations of seismological studies that could be included in future missions to the Solar System.

Session Chairs
Sharon Kedar <>

Steve Vance <>

Nicholas Schmerr <>


Estimating Earthquake Hazard from Geodetic Data

Geodetic techniques such as GPS and InSAR provide a critical constraint for quantifying earthquake hazard by recording the active accumulation of tectonic strain across seismogenic faults. Geodetic observations are particularly important in regions with sparsely mapped faults and/or few geologic slip rate estimates, such as inland Alaska, and in regions with known seismic hazard but broadly distributed strain, like the Basin and Range. However, geodetic estimates of fault slip rates can vary significantly for a single fault or region and may differ from geologic rates on the same fault. These discrepancies may reflect model assumptions since geodetic observations of the interseismic phase of the earthquake cycle must be interpreted in the context of a prescribed deformation model. They may also reflect transient processes due to post-seismic relaxation, glacial isostatic adjustment, and aseismic slip events that bias inferred interseismic deformation rates and, in turn, long-term fault slip rate estimates. We invite contributions that describe the application of geodetic data to earthquake hazard estimation in a variety of settings worldwide. We also seek contributions that present new approaches to addressing the challenge of effectively incorporating geodetic information into seismic hazard assessment. Some questions of interest include:

  • How can we best utilize geodetic observations in regions with few mapped structures or regions with low strain rates but known seismic hazard?
  • What is the role of off-fault deformation in geodetically observed strain rates, and what fraction of deformation occurs between major faults?
  • Can we identify the cause of discrepancies between geodetic and geologic slip rate estimates for the same fault?
  • By what metrics should geodetic models be assessed?
  • How do we assess uncertainty and the impact of modeling assumptions?
  • How do we estimate long-term fault slip rates in the presence of transient deformation signals (e.g., glacial isostatic adjustment, postseismic relaxation, slow slip events, etc.)?

Session Chairs
Jeff Freymueller <>

Elieen Evans <>

Jessica Murray <>


Fault Mechanics and Rupture Characteristics from Surface Deformation

High-quality surface data (e.g. point clouds, digital elevation models, and digital imagery) have become more readily available and easier to process and analyze with advances in acquisition technologies and computer processing capabilities. Accurate renditions of co- and post-seismic surface deformation permit characterization of fault and damage zone properties for scales and at resolutions that were not previously possible. This session addresses advances in earthquake and fault science using the newest generation of digital imagery and topography data. We encourage submissions that use continuous surface data (e.g. lidar, structure-from-motion, InSAR, UAVSAR, pixel tracking) to study fault mechanics and properties, including damage zone width and asymmetry, near and far-field displacement fields, shallow slip deficit, and scarp morphology and degradation.

Session Chairs
Lia Lajoie <>

Kendra Johnson <>

Edwin Nissen <>


Fine Scale Structure of the Crust and Upper Mantle

Recent advances in seismology have enabled increased resolution of structure in the crust and upper mantle, such as refined images of the Moho, sharp boundaries at the base of or within oceanic lithosphere, the lithosphere-asthenosphere boundary beneath continents, mid-lithospheric discontinuities, depth resolution of both azimuthal and radial anisotropy, etc. This session will highlight both new techniques for resolving structure and results that bear on geodynamic questions. Lev P. Vinnik, who will receive the Reid Medal in 2017, will give a key note lecture in this session.

Session Chairs
Peter Molnar <>

Barbara Romanowicz <>

Steven Roecker <>


Forecasting Aftershock Sequences in the Real World

Over the last two years, seismologists have produced forecasts for a number of aftershock sequences including the ongoing Christchurch, New Zealand, earthquake sequence which began in 2010 with the M7.0 Darfield event, the 2015 M7.8 Gorkha, Nepal, earthquake, the 2016 M7.0 Kumamoto, Japan, earthquake, the 2016 M6.2 Amatrice, Italy, earthquake, the 2016 M5.8 Pawnee, Oklahoma, United States, earthquake, and earthquake swarms near San Ramon and Bombay Beach, California, United States. Each sequence has raised challenging situations for the calculation of earthquake probabilities and their communication to the public, emergency managers, and other users. As systems that make these forecasts on a routine basis become operational we need to capture these lessons in the numerical software and presentation methods. We invite presentations on the application of earthquake clustering problems to these real-world situations as well as discussions of challenges faced in modelling and communication of forecasts; this could include related advances in statistical seismology and the social science of communication.

Session Chairs
Andrew Michael <>

Matt Gerstenberger <>

Warner Marzocchi <>


From Field Site to Data Center: Network Innovations for Earthquake Early Warning

With the advent of Earthquake Early Warning (EEW), seismic networks must now process real-time data within several seconds. Robust station architecture, reliable low-latency telemetry links, and streamlined data acquisition workflows are necessary for successful EEW systems. Networks must include multiple layers of redundancy while remaining highly secure, because as earthquake alerts become public and widespread, EEW systems may become prime targets for hackers. We invite you to share your innovations and challenges in this new era of seismic data acquisition. From the field site to the data center, how have you improved your network’s robustness, reliability, and security?

Session Chairs
Christopher Bruton <>

Rayo Bhadha <>


The Future of Past Earthquakes

The broad field of earthquake geology, which includes paleoseismology, provides approaches for quantifying the longer term behavior of active structures and active regions in time and space. Since the mid-1960s, when trenching was first used for simple fault location primarily in California, investigations of the rupture behavior of seismogenic structures have spread worldwide to all tectonic settings including subduction zones. Using improved and new techniques for dating geologic deposits and geomorphic surfaces, incorporating high resolution ground-based and satellite imagery for measuring coseismic surface and longer-term displacements, and investigating sites with long records of earthquake occurrence and event slip, earthquake geologic studies have expanded our four dimensional understanding of active earthquake systems and provided fundamental data for seismic hazard analysis.

This Special Session will include invited and contributed papers that present the current status and future directions of research in earthquake geology. We encourage papers examining all tectonic settings, fast and slow, and especially those incorporating new concepts, methods, and data that: a) define single-source and regional earthquake cycles; b) quantify earthquake rupture recurrence and slip models and their uncertainties; c) provide comparisons between short-term deformation rates from GPS, InSAR, and historical seismic moment release estimates with longer-term geologic slip rates and earthquake recurrence rates; d) develop insights into controls on dynamic rupture propagation and improve estimates of paleo and future fault rupture lengths; and e) use paleoseismic observations to suggest new constraints in modeling seismic hazard.

Session Chairs
David Schwartz <>

Ramon Arrowsmith <>

William Lettis <>

Koji Okumura <>

Daniela Pantosti <>

Thomas Rockwell <>


Geoacoustics: Infrasound and Beyond

Acoustic waves encode information about events occurring at or above the Earth’s surface, and they often image wind and temperature fields in regions inaccessible to most other measurement techniques. Thus, atmospheric acoustics is both a vital complement to seismic monitoring as well as a means of investigating signals that interact poorly with the solid Earth. We encourage contributions from the many diverse subfields of geoacoustics including signal analysis, propagation modeling, source physics, and sensor technology.

Session Chairs
Daniel Bowman <>

Stephen Arrowsmith <>

Omar Marcillo <>

Ground Motions and GMPE’s
This general session brings together a collection of presentations with the common theme of Ground Motions and Ground Motion Prediction Equations (GMPEs).

Session Chairs
Rich Briggs

Gavin Hayes <>


Importance of Long-Period Ground Motions in Seismic Design of Structures.

Records from instrumented structures clearly show that long-period ground motions are an important factor affecting the response of flexible structures, such as tall buildings, long bridges, and base-isolated structures. Large earthquakes can generate such waves at distances far beyond those considered in seismic hazard assessment. There is a need for a more accurate description of long period ground motions in seismic design codes.

This session invites papers related to the long period ground motions and their effects on structures, including the characterisation of long-period motions for seismic design, recorded response of structures to long-period motions, and modifications of attenuation equations and response spectra to better incorporate long-period motions.

Session Chairs
Erdal Safak <>

Eser Cakti <>


Induced Seismicity – The European Perspective

Different to North America, fracking in Europe is still in experimental stage, and waste water injection is limited to smaller volumes. Thus the most problematic cases of induced seismicity in public concern stem from conventional gas production (depletion), underground gas storage, geothermal and mining operations, and some dam induced events. Also legal aspects differ fundamentally since land ownership in Europe is restricted to shallow surface while any royalties from subsurface exploitation go directly to state budgets. Lack of personal benefit and densely populated areas caused massive public concern even after moderate seismicity. It resulted in servere reduction of production (Groningen gas field/NL) to permanent stop (Mirandola oil field/IT), canceled project developments (Basel geothermal/CH and Castor gas storage/ES), and severe delays in fracking conventional, e.g., tight gas reservoirs. All interventions were causing significant economic loss, and raised high regulatory demands for future planning. Our session focusses on case studies, modelling, and design of regulatory measures for the addressed situations, and comparison to US and Canadian approaches.

Session Chairs
Manfred Joswig <>

Joshua White <>

Mariano Garcia-Fernandez <>

Integrated and Geophysical Investigations for Site Characterization of Critical Facilities and Infrastructure
Development of a comprehensive geologic and geotechnical model is an essential element for siting and design studies of critical facilities and potentially aging infrastructure such as large LNG and nuclear facility foundation footprints, levees, dams, and linear alignments for pipelines. Multi-disciplinary investigations, including a range of geophysical, aerial, surface, subsurface, field, and laboratory testing, are required to develop a defensible and dependable site model; e.g., including multiple independent methods to derive critical design inputs such as shear wave velocity for seismic site response. Significant advances in geophysical exploration and processing, geospatial data collection and analyses, surveying, remote sensing and drone technology, and field testing have made large integrated field investigations more economical and dependable. Tricky site and subsurface conditions previously notoriously difficult to characterize, such as underground voids from karst or mining, are now being evaluated by investigation programs that integrate the latest non-intrusive and intrusive methods.

This session is intended to encompass the broad range of approaches used to achieve site characterization objectives. Topics of interest include airborne and land-based survey and measurement, geophysical surveys (e.g., HVSR, SPAC, SASW, MAM, MASW, IMASW, ReMi, down hole and cross hole seismic), destructive subsurface exploration and testing, and development of integrated geoscience databases and models. Examples are sought where multiple measurement methods of critical design parameters were applied for input to foundation evaluation, seismic response, soil-structure interaction, fault characterization, subsurface void detection, marine paleoseismology, IBC Site Class, liquefaction susceptibility, and mining applications. Advances in passive and active seismic sourcing and acquisition approaches are of interest. Also invited are updates on the Consortium of Organizations of Strong Motion Observation Systems (COSMOS) and the Development of the International Guidelines for the Application of Non-Invasive Geophysical Techniques to Characterize Seismic Site Conditions. Discussion of the challenges of meeting end-user expectations and objectives is encouraged. Defining the 3-dimensional distribution of geologic features and geotechnical conditions can now be performed to a degree that was unprecedented even 5 to 10 years ago, and this session invites discussion of advancements to integrated approaches.

Session Chairs
Jamey Turner <>

Jeffrey Bachhuber <>

Osman El Menchawi <>

Daniel O’Connell <>


Intraplate Earthquakes: Central and Eastern North America and Worldwide

Low strain rates and long recurrence intervals pose particular challenges to our understanding of the characteristics of and mechanisms responsible for seismicity in plate interiors. Nevertheless, although large historic intraplate earthquakes are less frequent than their plate-boundary counterparts, when intracontinental seismicity intersects with society it can have damaging effects.

This special session seeks to span the spectrum of studies on intraplate seismicity: its spatial and/or temporal distribution, scaling relationships, the role of crustal and/or upper mantle structures and dynamics, and seismic hazard implications. We invite contributions from new results derived from the use of EarthScope Transportable Array data and from studies worldwide.

Session Chairs
Lillian Soto-Cordero <>

Christine Powell <>

Will Levandowski <>

Machine Learning and its Application to Earthquake and Explosion Signal Analysis
This session focuses on the application of machine learning techniques to the analysis of seismic, infrasound, hydro-acoustic, remote sensing, electromagnetic, and other signals. The goals of machine learning applied to these signals include improved signal and event detection, phase identification, event discrimination, signal association, explosive yield estimation, and general signal and source characterization.

Session Chairs
Timothy Draelos <>

Hunter Knox <>


The Mw7.8 Kaikoura Earthquake

The Mw7.8 Kaikoura Earthquake of November 13, 2016 was the largest on-land earthquake to affect New Zealand in recorded history. It is the fourth earthquake larger than M7 to occur in New Zealand over the last 7 years, equating to much higher rates than the background and suggesting the possibility of strong temporal clustering. The earthquake occurred in a region of complex tectonics in which the dominant accommodation of plate convergence transitions between subduction to the north and continental strike-slip to the south. The event was geometrically complex, with numerous mapped surface ruptures and surface displacements of over 10 meters. The earthquake produced a tsunami with recorded tide-gauge measurements over 2 meters. Notably, the event also triggered numerous slow-slip events on the subduction system to the north of the earthquake. In this session, we invite contributions covering all aspects of this earthquake including but not limited to studies of clustering and triggering, source processes, slow slip processes, and statistical characterization of the sequence.

Session Chairs
Bill Fry <>

Matt Gerstenberger <>

Novel Approaches to Understanding Active Volcanoes
Recent advances over a range of geophysical techniques offer unique opportunities for improving our understanding of active volcanic systems. New developments in volcano seismology have allowed for the identification of several categories of volcanic seismic events, and more definitive interpretations of these events in terms of different physical processes. Novel approaches in tomographic and other seismic methods and the increasing capability for deploying large N-arrays at volcanoes allow for a more precise picture of magma storage and migration to emerge. Widespread availability of continuous seismic data, often analyzed in conjunction with other data streams, has facilitated many studies aimed at better constraining the dynamic nature of volcanic unrest. These studies may help to more accurately track and forecast volcanic activity through time. In this session, we welcome studies that employ novel geophysical methods and/or new datasets to better understand the distribution and migration of magma and volatiles at active volcanoes. We are especially interested in studies that combine seismology with other monitoring or modeling techniques, such as ground deformation, gas monitoring, infrasound, petrology, and fluid dynamics of magmatic systems. One of the seismological aspects we wish to emphasize in this session is the interaction of magma with hydrothermal systems and the resulting seismic signatures.

Session Chairs
Ninfa Bennington <>

Stephen McNutt <>

Jeremy Pesicek <>

Richard Aster <>

Matthew Haney <>

Numerical Modeling of Earthquake Ground Motion, Rupture Dynamics and Seismic Wave Propagation
Continuous development of numerical modeling methodology in seismology is not only driven by emerging requirements in observational seismology (e.g., the advent of very dense seismic arrays;demand for near-real-time simulations; the multi-scale, multi-physics modeling of seismic phenomena; etc.), but also by developments in the mathematical sciences, and through the adaptation of methods originating in other scientific fields. Moreover, future methods for very large scale simulations will be increasingly influenced by (and may in turn influence) the evolution of computer architectures and programming models.

This session is a forum for presenting advances in numerical methodology, whether the principal context is observational, mathematical/numerical, or computational.

We invite contributions focused on development, verification and validation of numerical-modeling methods, and methodologically important applications especially to earthquake ground motion,rupture dynamics and seismic noise. We encourage contributions on the analysis of methods, fast algorithms, high-performance implementations, large-scale simulations, non-linear behavior, multi-scale problems, and confrontation of methods with data. We especially encourage contributions related to the fast-emerging field that integrates dynamic event modeling with simulation of the full seismic cycle.

Session Chairs
Peter Moczo <>

Steven Day <>

Jozef Kristek <>

Observations and Mechanisms of Anthropogenically Induced Seismicity
Human-induced earthquakes continue to be on the forefront of seismological research, not least due to the series of recent earthquakes above M4 close to disposal and hydraulic fracturing wells in Oklahoma and British Columbia, including the Mw5.8 Pawnee earthquake, the potentially largest induced earthquake to date.

The present view of induced seismicity has been refined substantially over the past years and decades, emphasizing that induced pressure changes and elastic stress relaxation processes are the dominant mechanisms for inducing earthquakes. In addition, several studies highlighted that induced earthquake sequences can be identified by statistically significant deviations from stationary behavior. Such deviations include for example increasing background rates, which facilitate induced earthquake detection even in regions with much previous seismic activity. Physical differences between induced and tectonic earthquake ruptures are still debated and identification of potential differences is hindered by limited monitoring resolution. Such differences are detectable in small-scale laboratory and meso-scale controlled injection experiments, which produce much plastic deformation and aseismic slip. In addition, it has been recognized that the specific geological setting is pivotal for the potential to induce earthquakes. Several observations suggests that vertically confined but laterally extensive, high-permeability reservoirs, overlying crystalline basement formations are associated with relatively far reaching pore pressure diffusion and transmission too seismogenic depth resulting in higher induced seismicity potential.

While the present advances are encouraging there are many outstanding scientific questions that prevent effective mitigation strategies. These outstanding issues include but are not limited to constraints on maximum magnitudes and focal depth, the importance of the preexisting stress field and secondary earthquake triggering, the role of fault damage zones and high permeability channels, and potentially characteristic differences of induced earthquake source spectra and moment tensors.

We solicit laboratory, theoretical and observational studies that examine induced seismicity sequences and the contributions of fluid pressures and elastic stresses. We specifically invite contributions that focus on mechanisms of and mitigation strategies for induced earthquakes.

Session Chairs
Thomas Goebel <>

Thomas Braun <>


Ivan Wong <>

Justin Rubinstein <>

Overcoming Challenges in Seismic Risk Communication
More than half of the U.S. population lives in areas of moderate to high seismic risk. However, this risk can be difficult to convey, and is often not well understood by lay populations. This session explores the challenges of communicating seismic risk and presents proven or proposed solutions. Topics considered include but are not limited to: seismic hazard maps; induced seismicity; low-probability, high-consequence events in the Heartland; life-safety vs. performance-based earthquake engineering; preparing for megaquakes; and aftershock risk communication. This session draws from multiple disciplines, including: geophysics, seismology, structural engineering, emergency management, social sciences, and risk communication.

Session Chairs
Sean McGowan <>

Taojun Liu <>

Paleoseismology of Subduction Earthquake Cycles
Coastal, lacustrine and offshore paleoseismology assess the geological record of earthquakes over multiple cycles of strain accumulation and release. These studies provide critical information that advance understanding and modelling of seismic hazards, including associated tsunami, at all major subduction zones. Contributions to practical earthquake hazard assessment include the identification of great (magnitude 8 or 9) earthquakes during the Holocene where instrumental seismicity detects moderate to large (magnitude 6 or 7) earthquakes or none at all; estimating recurrence intervals of great earthquakes; and defining along-strike and down-dip patterns of rupture on the megathrust. Since publication of the seminal paper (Atwater, 1987) and widespread adoption of well-tested field and analytical methods debate moved on to questions critical for hazard assessment, emergency planning and international building code design (Mueller et al., 2015). Key issues include the extent of past great earthquake ruptures, the identification of boundaries between rupture patches, the persistence or transient state of these boundaries over multiple earthquake cycles, recurrence intervals of great earthquakes along strike, the role of aseismic slip, and whether parts of plate boundaries that are currently creeping have generated great earthquakes in the past and may do so again in the future.

We invite contributions that address these issues through field-based observations, historical reconstructions of earthquakes that occurred prior to global seismic networks, and modelling. Studies that combine multiple approaches are encouraged.

Session Chairs
Rob Witter <>

Ian Shennan <>

PSHA Source Modeling: Approaches, Uncertainty and Performance
Source modeling in probabilistic seismic hazard analysis (PSHA) is evolving rapidly in response to increasingly complex source models, increasingly parameterized ground motion models (GMMs), and a desire in most applications to better understand the epistemic uncertainties associated with each. The recently completed Pacific Earthquake Engineering Research (PEER) Center’s PSHA code verification project provided an opportunity to compare results from a variety of public and private codes. While there was good agreement between the codes for relatively simple source models, the project spawned rich discussion and exposed a broad variety of modeling approaches with regard to more complex models where, for example, hanging-wall terms were considered, the depth distribution of ruptures were a focus, and approximations of the finiteness of point sources were applied, among others. A common theme that emerged was that convergence between codes could often be attained by increasing the discretization of different model components, for example, the distribution density of point sources or the number of magnitude bins in magnitude-frequency distributions, with commensurate increases in processing time.

Whereas general engineering applications of PSHA have long focused on mean hazard, increasing attention is being paid to understanding the associated uncertainties that are usually considered in site-specific analyses. Such uncertainties are often quite large, and this raises the questions: How does one balance modeling choices in light of uncertainty and performance considerations? At what point do increases in model complexity cease to add value to a PSHA? We invite submissions that focus on all aspects of PSHA source models and the uncertainties associated with the parameterization thereof. We are particularly interested in generating discussion on and sharing results that exhibit the sensitivity of hazard values to alternate modeling choices. Presentations should frame those choices in the context of both source and GMM uncertainty with a focus on what is most important for the particular PSHA application at hand.

Session Chairs
Peter Powers <>

Christie Hale <>

Recent Advances in Earthquake Triggering and Aftershock Forecasting
When a major earthquake strikes, the resulting devastation can be compounded or even exceeded by the subsequent cascade of triggered seismicity. Recent examples are the M6’s Kumamoto 2016 events in Japan followed by a M=7.0 almost within a day and the raising concerns after the M=6.2 Amatrice earthquake in Central Apennines, relatively close to the 2009 L’Aquila earthquake. This session focuses on recent progress of physics-based and statistical aftershock forecasts but also on advances in understanding other types of earthquake triggering including remote dynamic triggering and tremor.

We invite contributions focusing on the challenges behind understanding earthquake triggering, improving operational forecasts and how our observational monitoring capabilities enable us to develop skillful models. Related topics include: operational earthquake forecasting models, aftershock occurrence statistics, real-time earthquake catalogs and the uncertainties behind seismic parameters, forecast validation, triggered tremor and remote dynamic triggering following regional and global events.

Session Chairs
Margarita Segou <>

Andrea Llenos <>

Recent Advances in Very Broadband Seismology
Observational seismology is fundamentally limited by our ability to record seismic signals across a very large bandwidth. The sensitivity of modern seismic instrumentation to non-seismic noise sources as well as other undesirable signals can limit our ability to record seismic events with high fidelity. The purpose of this session is to communicate recent advances in seismic instrumentation and deployment methods, as well as observations that highlight the heavy demands on instrumentation of very broadband seismology. Abstracts that highlight recent advances, techniques, or methods for seismic instrumentation, seismic network advances, or advances in Earthquake Early warning instrumentation are encouraged. We also encourage abstracts that focus on long-period or high-frequency seismology that could show limitations in our ability to record such signals.

Session Chairs
Adam Ringler <>

David Wilson <>

Robert Anthony <>

Recent Innovations in Geophone Array Seismology
The availability of geophone systems that allow continuous recording of seismic signals has opened up many new directions and applications in seismology research. Compared to broadband sensors, these geophone systems are generally cheaper and easier to deploy. These systems can be rapidly deployed (e.g., important for aftershock studies) and have a minimal environmental impact (e.g., important in sensitive areas). The low cost and ease of deployment also allows these instruments to be deployed in very large numbers, as “large N” arrays, which can reduce or eliminate spatial aliasing by recording a well-sampled wavefield. These geophones typically have a corner frequency of 5-Hz or 10-Hz and can record single or 3-component data. As a result, they are ideal for crustal-scale, high-resolution imaging studies using both active and passive sources.

In this session, we invite abstracts that are related to geophone array, full wavefield, or “large N” seismology, broadly defined. Studies can include, but are not limited to, instrument/sensor development, ambient noise tomography, active-source and earthquake seismology, and microseismicity, aftershock, and other environmental seismic signal monitoring. We particularly encourage abstracts that are related to the IRIS Oklahoma community full-wavefield experiment.

Session Chairs
Fan-Chi Lin <>

Marianne Karplus <>

Recent Moderate Oklahoma Earthquakes: Widely Felt and Often Damaging
While historically moderate earthquake (M5-6) are rare in Oklahoma, recently the State has experienced an unprecedented number of moderate events. First, on February 13th, 2016, a Mw 5.1 earthquake occurred near Fairview, Oklahoma. On September 3rd, 2016, near the city of Pawnee, Oklahoma experienced its largest historic earthquake (Mw 5.8). Most recently, on November 6th 2016, a Mw 5.0 earthquake occurred near Cushing, Oklahoma, resulting in significant damage to homes and businesses. All of these moderate earthquakes have occurred in a region of Oklahoma that has seen an unprecedented increase in earthquake rate, largely considered to be caused by an increase in wastewater injection. As earthquakes of this size are uncommon in the Central and Eastern U.S., these events present a unique opportunity to improve our understanding of intraplate events. As well, the wide variability in their seismic characteristics and their proximity to wastewater disposal presents a unique dataset to explore the complex link between injection and seismicity. We invite papers on a wide variety of subjects related to these earthquakes including, but not limited to: (1) constraining and comparing the source characteristics of these events; (2) describing observed ground-motions and intensities; (3) investigating the potential relationship between these events and wastewater disposal; (4) exploring the societal impacts of the earthquakes in terms of preparedness, business impacts, and oil and gas regulatory and emergency management response. Our aim is to have a wide-variety of presentations that explore a broad range of observations from these events.

Session Chairs
William Yeck <>

Robert Williams <>

Justin Rubinstein <>

Regional Variations in Seismological Characteristics: Implications for Seismic Hazard Analysis
The prediction of potential earthquake shaking that could occur at a site from nearby earthquakes is a key part of a seismic hazard assessment study. This is achieved by employing empirically derived ground motion models (GMM), also called ground motion prediction equations (GMPEs). An important issue in seismic hazard analysis is the regional variation in ground motions and the resulting variability in the prediction for the median motions and the aleatory variability. The increase in available global databases of earthquake records has made the regional variations in the ground motions become rather evident. Recent NGAWest2 (e.g., Boore et al., 2014) and European models (Kuehn and Scherbaum, 2016; Kotha et al., 2016) have included the regional variations in their median predictions. These variations were essentially identified/accounted in terms of the variation in inelastic attenuation in their models. Additionally, the near source hazard can be more influenced by regional variations in source properties, e.g. fault rupture kinematics and stress drop (stress parameter). In the context of seismic hazard analysis, it is also important to study the regional variation in associated uncertainty along with the median ground motions.

Thus, in order to have a robust basis for model selection and thereby constraining the epistemic uncertainty, additional research on the regional variation of ground motion and on the regional variations in physical/seismological characteristics (and corresponding epistemic uncertainties in the parameterization) are needed. In this session we welcome studies focused on investigating regional variation in seismological characteristics such as in source (stress drop and fault kinematics), attenuation and site characteristics. In addition to research in the engineering seismology and seismic hazard domain, we also encourage submissions related to core seismological/geophysical studies that can provide useful guidance to ground motion model development. The subsequent step (after selection of ground motion models) is to adjust the ground motions to account for regional variations. Thus studies involving strategies/methods for physically consistent adjustment of median ground motion and aleatory uncertainties are also encouraged for the submission.


Boore, D. M., Stewart, J. P., Seyhan, E., & Atkinson, G. M. (2014). NGA-West2 Equations for Predicting PGA, PGV, and 5% Damped PSA for Shallow Crustal Earthquakes. Earthquake Spectra , 30 (3), 1057-1085.

Kotha, S. R., Bindi, D., & Cotton, F. (2016). Partially non-ergodic region specific GMPE for Europe and Middle-East. Bulletin of Earthquake Engineering , 14, 1245-1262.

Kuehn, N., & Scherbaum, F. (2016). A partially non-ergodic ground-motion prediction equation for Europe and the Middle East. Bulletin of Earthquake Engineering , 14(10), 2629-2641.

Session Chairs
Sanjay Bora <>

Adrian Rodriguez-Marek <>

Marco Pagani <>

Scaling and Empirical Relationships of Moderate to Large Earthquakes: Re-scaling or Re-thinking?
Magnitude versus rupture size is a key point in many seismological fields, and in seismic hazard assessment in particular.

Despite the efforts spent by the international community on this topic, the basic dataset for deriving empirical relationships or confronting theoretical models gathers few hundreds of events, and the homogeneity in the measure (of energy release and fault/rupture size) is not always guaranteed.

In particular moderate earthquakes are poorly represented in those relationships. The session aims at debating: 1) the structure and upgrading mechanisms of a repository for the collection of certified data; 2) the contribution of new technologies (e.g. INSAR data) to acquire data; 3) the lessons learned in case studies, about generalisation or regionalisation of magnitude versus size relationships.

Session Chairs
Laura Peruzza <>

P. Martin Mai <>

Lucilla Benedetti <>

Seismology Software Tools That Improve What We Do and How We Do It
In today’ world the number of scientific software tools that exist freely and in the open is staggering. We invite implementers and users alike to present the software tools they use, build, operate, contribute to, and practice with, to share strengths and improvements that we all can gain from in seismology. It may be data acquisition tools converging on standards supporting more data across more instrument types (e.g. search indexes, time series databases, NoSQL), or data analysis tools with inline visualizations (e.g. IPython notebook, Kibana), data parsing and processing tools (e.g. ObsPy, R), web services following common standards for broader and easier data sharing (e.g. GeoJSON, QuakeML), or open source encouraging broader collaboration (e.g. GitHub, Docker Hub). There is great potential in what software tools can help us accomplish. Share your tools, standards, and best practices that can improve how we do seismology.

Session Chairs
Michelle Guy <>

Eric Martinez <>

This general session brings together a collection of presentations with the common theme of Seismotectonics.

Session Chairs
Rich Briggs

Gavin Hayes <>

Source Discovery Using Differential Methods: Applications to Explosion Monitoring
Geophysical techniques for explosion monitoring have advanced spectacularly in the nearly 60 years since the first fully contained underground nuclear test Rainier was conducted in September 1957 in Southern Nevada, and significantly in the nearly 20 years since the CTBT (Comprehensive nuclear-Test-Ban Treaty) was signed in September of 1996. Many current seismic techniques use differential methods (e.g. ratios, differences, cross-correlation, etc.) to significantly lower detection thresholds, obtain unprecedented relative location precision and determine more accurate source parameter differences (e.g. magnitude, mechanism, depth, etc.). For spatially clustered sources (e.g. nuclear test sites, earthquake sequences, injection wells, etc.) where differential techniques effectively cancel path effects, they are yielding exciting new insights into seismic source processes.

One area of high interest is North Korea (DPRK – Democratic People’s Republic of Korea). North Korea is the only country to have conducted declared nuclear tests in this century, five in total, two of them in 2016 (as of this writing on October 1st). In this session we seek studies applying differential methods to the DPRK and other nuclear explosives testing sites to explore the advances and challenges of applying these techniques to improve monitoring capabilities. We seek related studies that apply differential techniques to other source types and regions to improve processing and geophysical understanding. We also welcome related studies that explore new datasets, techniques and analyses to advance explosion monitoring.

Session Chairs
William Walter <>

Joshua Carmichael <>

Steven Gibbons <>

SSA-ESC Joint Session on Advances in Geotechnical Borehole Arrays, Data and Analyses
The design objective of geotechnical borehole arrays is to capture instrumental observations of the earthquake effects associated with the penultimate event in the region in which the array is deployed. The broader objective is to capture a suite of earthquakes covering a range of ground motions and strain levels that include the effects of the near-surface geology from linear through nonlinear behavior. These observations are the empirical case histories that are used to validate the constitutive models in site-specific ground response analysis, providing direct in situ evidence of soil nonlinearity and liquefaction. Geotechnical borehole array data when coupled with nearby structural arrays provide insights into soil-foundation-structure interaction.

This session aims to bring together the Engineering, Seismological, and Geophysical communities and create a platform for discussion and exchange concerning borehole arrays, data, and applications. We welcome contributions from all aspects of borehole data analysis, including, but not limited to: interferometry, material properties in the linear and non-linear range, liquefaction, site response, amplification, and attenuation. We encourage novel and hybrid applications of vertical arrays, including coupled subsurface-and-superstructure arrays. We also seek to hear from those installing new arrays, compiling new databases of downhole data, and to discuss new possibilities for applications.

Session Chairs
Jamison Steidl <>

Ramin Motamed <>

Umit Dikmen <>

Stefano Parolai <>

The Subduction Zone Observatory
The subduction zone observatory (SZO) concept is a multidisciplinary facility stretching along a significant portion of one or more of the circum-Pacific subduction zones, providing a comprehensive suite of onshore and offshore observations to understand the entire subduction zone system.

The success, knowledge, and experience of EarthScope provides a launching point for the creation of such a facility. The observatory’s goal is to provide an integrated, interdisciplinary approach, with broad international participation, to understand subduction zones as complex systems. SZO research will illuminate the underlying processes that govern subduction zones at multiple temporal and length scales, from earthquake rupture to long-term tectonics, and have significant societal relevance, given the population centers adjacent to subduction zones are subject to earthquake-, tsunami-, and volcano-related hazards.

Seismological, geodetic, and tsunami related investigations are fundamental to the SZO’s goals. We invite contributions that address the basic question of what the science targets of the SZO should be. Furthermore we encourage contributions from recent results in subduction zone science and hazards that exemplify the potential advantages of a multidisciplinary and international facility.

Session Chairs
Diego Melgar <>

Lee Liberty <>

Jeff Maguire <>

Theoretical and Methodological Innovations for 3D/4D Seismic Imaging of Near-surface, Crustal, and Global Scales
This session will focus on recent theoretical and methodological developments of seismic imaging and monitoring (i.e., time-resolved imaging) techniques to better understand the Earth´s structure on various scales. In previous years, imaging techniques have developed rapidly thanks to the advent of high-density networks, new modeling techniques, and unprecedented computation capacities. This includes, for example, seismic noise surface wave tomography, accurate estimation of source locations of microseismic events, and full-wave inversion with active/passive sources. However, significant problems, both well-known and lesser-known, remain. These include model resolution, uncertainty, reproducibility, nonlinearity, and non-uniqueness.

We invite novel approaches for solving common practical problems for 3D/4D imaging. To this regard, we welcome innovations and advances in physics-based imaging, 3D/4D tomography, waveform tomography, new migration techniques, advanced signal processing, multi-component seismic noise correlations, monitoring and locating of velocity changes, and joint inversion of multiple geophysical observations. Presentations of ideas to overcome effects of structure outside the modeled region, uneven ray coverage, and limitation of resolution will be also included in this session. Studies that compare real-Earth results obtained using different methods, and assess repeatability, are particularly encouraged as well as methods to establish best practice for the proper implementation of synthetic reconstruction tests.

Session Chairs
Marco Pilz <>

Nori Nakata <>

Theoretical and practical advances in ambient noise and coda studies
The past decade has featured numerous advances in passive imaging using ambient noise and multiply scattered seismic coda from earthquakes or other sources. The inherent simplicity of many applications has generated a swath of mainstream tools and applications now being used over all frequency-wavenumber scales. With the advent of large-N networks and emerging opportunities for scattered and 4D seismological imaging, we seek contributions on refining our use of large datasets and diverse uses and applications related to further extracting accurate Green’s functions and physical parameters using seismic interferometry.

Session Chairs
Julien Chaput <>

Hsin-Hua Huang <>

To Tweet or Not To Tweet: Effective Use of Social Media for Citizen Science and Science Communication
The advent of social media has changed the way that people around the world communicate with one another. Young people in particular rely increasingly on social media, including Facebook and Twitter, rather than conventional news outlets, to stay abreast of current affairs. This development poses challenges as well as opportunities for Earth scientists interested in science communication to a broad audition. The challenges associated with the use of Twitter, for example, for serious science communication are manifest: “Tweets” are limited to 140 characters, and the free-for-all nature of the Twitter information network creates an echo chamber in which the signal-to-noise ratio can be low. The potential opportunities provided by social media sites such as Twitter, Facebook, and Instagram can be less apparent. Yet social media sites like Facebook and Twitter provide an important opportunity for crowd-sourced reporting and communication when a natural disaster occurs, as well as opportunities for broad dissemination of scientific results of interest to a broad audience, and a unique ability to reach teenagers and young adults. Twitter feeds can even be exploited for gathering of invaluable crowd-sourced data following earthquakes and other natural disasters. For this session, which will include introductory tutorials for social media newbies, we invite abstracts focused on the use of social media for both scientific research and science communication.

Session Chairs
Susan Hough <>

Julian Lozos <>

Christine Goulet <>

Paul Earle <>

Toppled and Rotated Objects in Recent, Historic, and Prehistoric Earthquakes
The main purpose of the session is to bring together researchers with diverse backgrounds (e.g., seismology, engineering, history, heritage conservation) who are interested in the behavior of objects, monuments, or simple structures during earthquakes and the stories which deformed, rotated or toppled objects can tell. The session will cover all aspects of toppled or rotated objects or simple structures which have suffered heavy deformation or damage during earthquakes. Topics will include: (1) observations, (2) documentation, (3) model building, (4) restoration, (5) mapping, and (6) correlation with geology.

Recent earthquake research has postulated correlation between the reaction of objects (monuments, columns, tombstones, etc.) and the seismic source in addition to local effects due to geological site conditions. As the laws of physics are time invariant, knowledge gained in reconnaissance surveys from well-studied instrumental earthquakes can reveal information about ground motions during historical and prehistorical earthquakes. Particular interest will be directed to man-made structures; however, due to similarities of the techniques used to study precariously balanced rocks and speleothems, contributions from these fields are also welcome.

Session Chairs
Klaus-G. Hinzen <>

Rasool Anooshehpoor <>

Understanding and Modeling Ground Motions and Seismic Hazard from Induced Earthquakes
Performing a probabilistic seismic hazard analysis (PSHA) for induced seismicity is very difficult because we have neither a complete understanding of the genesis and recurrence of induced earthquakes nor a comprehensive model for the ground motion excited by them. Whether there is a fundamental physical difference between natural and induced events is still an open question, and how any potential difference manifest themselves in the ground motion is of great interest. Furthermore, the level of seismic activity may be dependent on human activity, complicating any hazard analysis. We seek contributions that will help establish the modeling input parameters that are critical for the analysis, including controls on both seismic activity and ground motion, the building blocks of a PSHA. For earthquake activity, this may include including declustering earthquake catalogs or determining rates, hypocenters, or maximum magnitudes. By combining information on the state of stress, hydrologic properties of injection formations and the basement, and the locations and orientations of faults with injection data, we have the possibility of building predictive models that anticipate the seismic potential of an area based on its past history. On the ground motion side, we encourage contributions related to understanding if ground motion from induced events is similar or different to existing models, or how ground motion scales at very close distances to these shallow events. This could include testing of existing GMPEs, development of new empirical or simulation based GMPEs, or understanding of the source, path, or site controls on observed ground motion. We encourage submissions regarding the phsysical parameters controling ground motion genesis (such as stress drop or depth) or propagation (attenuation or other path effects). In particular, resolving if these stress drop of these events is similar or very different from that of other tectonic environments is of great interest. Addressing the trade offs in stress drop and hypocentral depth is also of great interest. We especially encourage novel, creative and ground-breaking presentations on concepts that contribute to advancing next-generation induced earthquake PSHA models.

Session Chairs
Annemarie Baltay <>

Daniel McNamara <>

Eric Thompson <>

Mark Petersen <>

Varied Modes of Fault Slip and their Interactions – Slow Earthquakes, Creep to Mega Quakes
Faults show a diverse mode of slips – from slow earthquakes, shallow creep to supershear rupture and damaging fast megathrust earthquakes. Slow earthquakes appear to play an important role in the seismic cycles of major faults. They typically occur at the edges of the seismogenic zone, and radiate seismic energy in the form of tremor, low and very low frequency earthquakes. Slow slips are often inferred to be the driving mechanism of migrating swarms of regular fast micro-earthquakes. Regular earthquakes including large damaging megathrust quakes, on the other hand, seem to show different source characteristics. How these different modes of fault slip operate and interact remains an enigma. In addition, frictional properties that control these modes are poorly understood. We invite abstracts on the diverse behavior of fault slip including but not limited to slow slip, tremor, low and very low frequency earthquakes, aseismic slip, fault creep and fast megathrust earthquakes. Multidisciplinary studies incorporating observations and modeling focusing on the mechanism and interactions of different modes of fault slip are encouraged.

Session Chairs
Abhijit Ghosh <>

Verification and Validation of Earthquake Occurrence and Hazard Forecasts
Earthquake occurrence, hazard forecasts (hazard maps) and nowcasts have long lagged behind similar applications, such as weather, economic, or population forecasts and nowcasts, in addressing issues of verification and validation. Validation asks how well the algorithm used to produce the forecast implements the conceptual model (“have we built the model right?”). Verification asks how well the model forecasts the observations that actually occur (“have we built the right model?”). In recent years, this situation has been changing, in part via adopting ideas from other forecasting applications. We invite papers dealing with issues such as defining forecast goals, improving forecasts with new data or methodology, testing forecasts against observations, assessing forecast uncertainties, and better using forecasts for hazard mitigation.

Session Chairs
Seth Stein <>

John Rundle <>

Mark Petersen <>