SSA 2014 Annual Meeting
The following thirty special sessions, grouped into seven categories, and six general sessions, have been organized for the 2014 Annual Meeting program. Click any session name to view the schedule and abstracts for that session.
Arrays, Imaging and Seismometry
Cold Climate Installation Techniques and Instrumentation Developments for Temporary and Long-Term Networks
Temporary and long-term seismic networks reach all corners of the globe. Over the last decade, the increased interest in glacier and polar seismology concerning climate research, and more recently, the move of USArray to Alaska, have raised expectations that temporary seismic stations will operate continuously in these extreme environments. Polar climates pose particular challenges to temporary and long-term networks and the instrumentation that is deployed. Cold temperatures, snow cover, freeze-thaw cycles and short daylight hours challenge the operational capabilities of these remote stations. Logistic constraints limit the size of deployable, off-the-grid power systems, and limited winter access dictates that equipment must operate for many months or years without maintenance visits, some blind even of state of health information. This session will focus on new developments in cold-climate seismic deployments, including enclosures, power systems, telemetry, instrumentation, and logistics.
Researchers have started to deploy the next generation of directly buriable broadband seismic sensors after years of building vaults to protect arguably observatory-grade sensors that were neither rugged nor water resistant, using shallow simple vaults that limited their noise performance. The debate of whether to chase the final 2-10 dB of noise floor in shallow vaults has shifted to the question of what are the signal-to-noise ratios required to collect enough events that will allow more successful deployments with limited logistics and minimal budgets? This session will present techniques and developments to enable broadband seismology to increase the number of successfully deployed stations with decreasing logistical budget requirements including use of other types of shorter-period sensors in mixed-mode arrays.
David E. Hawthorn
Enhanced recovery, injection well monitoring, microseismic monitoring, energy exploration, and reservoir characterization/monitoring are driving dramatic new commercial-sector seismic instrument development and analysis techniques in the energy industry. The associated multichannel capabilities are up to orders of magnitude greater than have been available to non-industry-aligned academic seismology. This expansion of monitoring and imaging scope has also produced renewed emphasis on the use of broader-band instrumentation at very large network/array scales. This session will encompass both the diverse scientific/industry opportunities associated with the deployment and analysis of very large numbers of seismographs, and opportunities for associated novel collaborations within the greater seismological and Earth science community.
In 2014 the USArray Transportable Array will begin deploying in Alaska, after ten years successfully crossing the entire lower-48 states. The arrival of the Transportable Array in Alaska presents an unprecedented opportunity to image one of the most seismically and tectonically active regions of the world. We encourage contributions highlighting results achieved already with USArray data or which provide the context and framework for discoveries to come. The goals of the session are to identify opportunities for characterizing structures of the crust (including basins and volcanoes), slab, and mantle using complementary data sets. Example data sets include onshore and offshore data, active and passive seismic data, ambient noise and earthquake data (local or teleseismic), and potential field data. We encourage submissions featuring techniques that harness large emerging data sets and modern computational methods.
Great Subduction Earthquakes
Of the nine largest subduction zone earthquakes documented since 1900, four have occurred in the last 10 years, including; 2004 Sumatra-Andaman Islands and 2005 Nias, Indonesia; 2010 Maule, Chile, and; 2011 Tohoku, Japan. Many of these earthquakes, together with their aftershocks and a host of “smaller” – but equally important – independent earthquakes have generated large databases of digital ground-motion recordings and macroseismic intensities. This session will discuss subduction zone ground-motion observations (both instrumental and macroseismic) for modeling hazard and risk globally. We seek contributions that address a range of questions, including: Can ground-motion models developed from one global database (e.g., Japan) be translated to another region (e.g., Alaska or Cascadia)? Are current magnitude scaling models appropriate for Great earthquakes? How do we model the ground-motion uncertainties? What macroseismic effects are commonly observed from these events? How can we leverage of modern and historical macroseismic data to inform ground-motion model development for hazard assessments? Are global monitoring seismic networks sufficient for monitoring large subduction events? How can we use this information to mitigate the potential impacts of future large subduction earthquakes?
Recent great earthquakes and their accompanying devastating tsunamis in Sumatra, Chile, and Japan highlight the need for subduction-zone histories that span the hundreds to thousands of years needed to sample the greatest events. Few instrumental measurements cover more than a fraction of the cycle of interplate strain accumulation and release at active subduction margins. Even on the few coasts with extensive historical archives, records are too short or incomplete to fully reconstruct the history of the greatest earthquakes and highest tsunamis. Without accurate reconstructions spanning multiple earthquake cycles, there is little hope of understanding the variables that control how megathrust ruptures nucleate and extend along subduction zones, how the highest tsunamis are generated and dispersed across ocean basins, and in assessing the hazards from these great events. The century to millennia-long recurrence times of these events dictates the use of an array of interdisciplinary techniques from, for example, the fields of stratigraphy, geomorphology, dating, paleontology, oceanography, and history, to determine the timing and characteristics of past events. This session will explore recent developments in reconstructing the histories of large earthquakes and tsunamis on active subduction margins worldwide. We especially encourage presentations comparing and contrasting earthquake and tsunami behavior at different subduction zones, presentations integrating multiple techniques to characterize earthquake and tsunami behavior, and descriptions of new and innovative methods of investigation.
Diverse Mechanisms of Subduction Zone Fault Slip: Exploring the Relationships Among Seismic Rupture, Transient Slip, and Steady Creep
The release of elastic energy at subduction zone faults can result in intense ground shaking over broad regions and sea floor displacement that generates immense tsunamis. Tectonic tremor and/or slow slip, commonly observed between the seismogenic zone and down-dip stable sliding, represents an intermediate mechanism for faults to accommodate plate convergence. Yet the relative location of these different slip behaviors varies among subduction zones both along-strike and along-dip. Additionally, some subduction zones accommodate strain through aseismic stable sliding within the depth range where large earthquakes are expected to occur. Why such variability exists (e.g., frictional, rheological properties, material heterogeneity, variations in fluid pressure) and how it affects great earthquakes (e.g., up-dip or down-dip extent of seismic rupture, incomplete inter-seismic coupling) is poorly understood. It also remains unclear whether these diverse mechanisms are consistent over time or what role they play in the earthquake cycle. The objective of this session is to showcase the current understanding on these topics, and we seek to combine a wide range of abstracts that utilize observations, theory, or modeling with aspects from seismology, geodesy, lab experiments, and field observations.
Harmony V. Colella
Emily C. Roland
Aaron G. Wech
Fifty Years of Tsunami Science: from the 1964 Earthquake and Tsunami to the SAFRR Tsunami Scenario - Advances in Tsunami Source Characterization, Numerical Analysis and Hazard Mitigation
In recent years, the study of tsunami hazard has evolved from the traditional numerical modeling environment to include loss estimates and mitigation measures, partly due to the large tsunami disasters of the last decade. For instance, the USGS SAFRR scenario for a large Alaskan tsunami's impact in California rolled out in 2013/2014 to coincide with the 50th anniversary of the 1964 Alaska earthquake and tsunami. This session brings together all the different facets of tsunami hazard analysis, from advances in source characterization, propagation and runup modeling to loss estimation and mitigation measures. The session will include several presentations on the SAFRR scenario, and we invite contributions in the broad range of tsunami research including tsunami source characterization in both deterministic and probabilistic framework, new techniques and technologies in numerical analysis and hazard mapping. Studies in the field of tsunami preparedness of the population, perception of risk, human behavior during the event and effectiveness of tsunami warnings are welcomed. We expect the contributed papers to help us better understand the missing pieces in the existing tsunami mitigation programs and improve resilience of coastal communities to tsunami hazards.
Hong Kie Thio
Great Earthquakes and Slip to the Trench (Seismological Society of Japan/Seismological Society of America Joint Session)
This session invites presentations about large and great earthquakes in convergent zones, especially those events that have significant slip on the shallow portion of the megathrust close to the trench. These types of seismic events, such as the 2011 Tohoku-oki earthquake, have the potential for producing very large tsunamis, as well as strong shaking, and the potential for triggering widespread landslides and liquefaction. We invite papers on to recent seismic and geodetic observations characterizing sources, constraints on the controlling structures and material properties, and modeling studies related to great subduction zone earthquakes.
Emily C. Roland
Ground Motions to Engineering
Advances in Seismic Imaging and Monitoring of Time-Dependent Variations: Civil Structures, Near-Surface, and Shallow Crustal Scales
This session will cover new developments in seismic imaging and monitoring, from the sub-meter-scale in engineering applications for controlling civil structures to the meter-scale in near-surface seismology, up to the kilometer-scale of shallow crustal seismology. Contributions dealing with controlled-source continuous or repeated observations to detect temporal variations of seismic velocity or other properties are especially welcome. We invite submissions relevant to theoretical and practical aspects using both active and passive seismic data, methodological studies, and studies aimed at developing new instrumentation. We aim to highlight progress of imaging and surveillance studies and related research in real-time seismic hazard monitoring.
From the Earthquake Source to Damage of Buildings: Bridging the Gap between Seismology and Earthquake Engineering
Seismologists and engineers with the capability to understand the scientific and technical features of physical and numerical models including the physics of earthquake source, wave propagation effects, site specific ground motion predictions and seismic vulnerability of structures, are key professional figures within the framework of seismic risk assessment and mitigation studies. Building these professional skills requires seamless cooperative efforts between earthquake scientists and earthquake engineers. This expertise is routinely employed and optimized by a number of governmental, academic and industrial stakeholders. With the aim of gathering and promoting the discussion amongst the aforementioned scientists and engineers, in this session we welcome innovative studies on the topics mentioned above, with strong emphasis placed on practical applications, characterized by a successful integration of seismological and engineering advancements, tailored to the mitigation of seismic risk.
Luis A. Dalguer
Recent and continuing efforts in broadband hybrid and deterministic modeling of earthquake processes indicate that we are approaching a junction where physics-based ground motion simulation techniques can be integrated with seismic hazard analysis, risk and loss assessment studies, engineering analysis and design. This session invites participants to contribute their work in the broader area of earthquake modeling and simulation (coupled) with engineering applications. Topics of interest include: high-frequency ground motion simulation; integrated earthquake simulation, end-to-end and/or rupture-to-rafters simulation; integration of nonlinear soil, surface topography and other site effects in simulation; local and regional simulations including soil-structure and site-city interaction effects; structural systems modeling, analysis and design using simulation synthetics as input; earthquake simulations coupled with GIS data; loss and damage assessment based on synthetic datasets; use of ground motion simulations for evacuation plans and emergency response.
The 1964 Alaska Earthquake was significant for many reasons – including extensive observations of ground failure. As we celebrate the 50th anniversary, we will look at recent earthquakes, including the 2011 Tohoku earthquake and the 2010-2011 Christchurch Earthquake that have provided new datasets on ground failures. These new datasets facilitate research that improves ground failure models and provides insight into ground failure mechanisms. This session will highlight developments in ground failure models with special focus on urban earthquake hazard. Among the ground failure hazards to be addressed are surface rupture, liquefaction and landsliding.
Various research and application areas in geophysics, seismology and engineering are strongly dependent on the seismic velocity and material models used in simulation today. While much progress has been done over the last decades in advancing such models, our knowledge about the geology and structure of the crust and its sedimentary basins and the near-surface geotechnical layers, as well as our modeling approaches to represent the mechanical properties of materials beneath the surface are somewhat limited. This session solicits contributions in the broad area of seismic velocity and material models and their application in earthquake (source and ground-motion) simulation. Topics of particular interest include but are not limited to: development of new and improvement of currently available community velocity models, description of velocity models software, discrete representation of velocity models used for simulation, verification and validation of velocity models, full waveform tomography and inversion, attenuation and/or quality factor rules, visco-elastic material models, off-fault and near-surface plasticity, initial stress conditions and elasto-visco-plastic models in simulations including material nonlinear behavior, integration of geotechnical data, and representation of heterogeneous media.
This session is targeted to highlight recent advances in the development and validation of ground motion simulation methods. Topics of interest include: formulation of new or updated simulation methods with description of parameterizations of the source, path and/or (nonlinear) site effects; models including small-scale heterogeneity in the source or surrounding medium or incorporating 3D complexity of the medium and/or mountain topography; methods for better constraining input; sensitivity of methods to ranges of plausible input parameters; and quantification of uncertainty in simulated ground motions. We also invite case histories comparing ground motions from various simulation techniques, as well as calibration and validation of methods against recordings and/or ground motion prediction equations. The session is open to a wide range of simulation methodologies, including deterministic and stochastic models of wave propagation, with stochastic, kinematic or dynamic models of the source description.
Kim B. Olsen
We invite contributions that fall within the broad category of site response analysis, including topics from advances in fundamental soil behavior modeling to simplified methods for mapping site response at the national and global scales. Site response has been a hotly debated topic between engineers and seismologists for decades. In the recent years, the two communities have reached consensus on the nonlinear nature and importance of site response as a constituent of ground motion predictions and seismic hazard assessment; faced with the ever increasing amount of recorded evidence in statistical studies, or pushing the envelope of high frequency ground motion simulations, many seismologists currently account for nonlinear soil effects in their studies. Thus, the classic debate has shifted towards more subtle and interconnected issues, such as the use of the average shear-wave velocity to 30 m (Vs30), empirical vs. theoretical modeling approaches, time-domain vs. spectral analyses, and the accuracy of fundamental modeling assumptions. Although different approaches can be cast as controversies, it is useful to see them as solutions to different problems rather than competing solutions to the same problem. For example, although a nonlinear time-domain analysis more accurately accounts for soil behavior than statistical correlations with Vs30, the latter approach may be the only option available for applications at sites where dynamic soil properties are unavailable. In this context, we encourage submissions to focus on the motivations behind their modeling choices, and to discuss the applications and scales where their approach is expected to be most beneficial.
Paleoseismology and Long-Term Records of Earthquakes
Geometric Complexities Along Strike-Slip Systems: New Insights on Seismic Hazards, Earthquake Behavior, and Fault System Evolution
Major, active strike-slip fault zones around the world often have discrete zones of deformation and elevated seismicity focused around restraining bends and other geometric complexities of the trace of the main strike-slip fault. Alaska contains two world-class examples of extreme deformation and complex seismicity patterns along major strike-slip fault systems – the Mount McKinley restraining bend of the Denali fault, and the Alaskan syntaxis associated with the Fairweather fault. With this meeting having these dramatic examples as a backdrop, we seek contributions that provide global insight into focused zones of deformation along strike-slip faults and their influence on earthquake rupture and recurrence behavior, fault system evolution and the differences in seismic hazards between the primary strike-slip fault and subsidiary faults. We welcome contributions from seismology, paleoseismology, thermochronology, structural geology, geodesy, and analogue/numerical modeling, exploring both theoretical studies and field-based examinations of restraining bends around the world, including (but not limited to) the well-studied examples from the San Andreas fault system, the major fault systems of central Asia and South/Central America, the Dead Sea fault, the North Anatolian fault, and the Alpine fault.
Sean P. Bemis
Characterizations of the timing, recurrence, displacement, and rupture extent of recent surface-faulting earthquakes provide key inputs for earthquake-probability forecasts and seismic-hazard assessments. This session will highlight recent advances in the fields of earthquake geology and paleoseismology from investigations of Quaternary-active faults. We invite abstracts that present 1) paleoseismic earthquake histories and improved estimates of earthquake recurrence, fault slip rate, and rupture extent; 2) techniques for investigating surface ruptures, such as remote sensing of surface deformation and offset (e.g., InSAR, GPS, and pixel tracking); and 3) objective methods of synthesizing multiple paleoseismic datasets. The goal of this session is to critically evaluate how detailed fault and earthquake characterizations inform our understanding of seismic hazard.
PSHA, Hazard Maps
About twenty M4 to M5.8 earthquakes have occurred since 2010 in the intraplate region of Central and Eastern North America. Most of these events were well recorded by ANSS and USArray seismographs and provide data that can contribute to reducing uncertainties in seismic hazard assessment. From recordings of these events we seek contributions providing insights into seismic source characteristics, aftershock behavior, attenuation, site response, crustal structure relative to characterization of seismic and aseismic regions, and building damage. All aspects of studies related to the 2011 M5.8 Mineral, Virginia earthquake are of particular interest.
The United States Geological Survey (USGS) plans to update the Alaska portion of the U.S. National Seismic Hazard Maps to produce science-based products that will be considered for inclusion in future building codes, risk assessments, and other public policy applications. These seismic hazard maps are based on our assessment of the “best available science” at the time of the update, and incorporate a broad range of scientific input models and parameters. We invite papers discussing new geologic and geophysical information on Alaska seismic sources (faults and seismicity) and ground motion models. In particular we are interested in new paleoseismic fault studies, geodetic and geologic combined inversions of fault slip rates, and ground motion models for subduction and crustal sources.
Development of 2014 U.S. National Seismic Hazard Maps and Their Implementation in Engineering Applications
The 2014 National Seismic Hazard Maps (NSHMs) produced by the United States Geological Survey (USGS) incorporate significant changes in the earthquake catalog, source models, and ground motion models. These seismic hazard maps are based on the USGS’ assessment of the “best available science” at the time of the update, and incorporate a broad range of scientific input models contributed by the seismological research community. The NSHMs are used to produce science-based products that will be considered for inclusion in future building codes, risk assessments, and other public policy applications. We invite papers that discuss major changes to the maps or to the input data and models (e.g., catalog, source models, ground motion models) since 2008; or discuss improvements in data, methods, and models that could be used in future maps. Papers that discuss the impact of the 2014 NSHMs on design maps and future building codes are encouraged.
In light of recent advances in earthquake science, data, and computational resources, probabilistic seismic hazard analyses (PSHAs) have increased in complexity. Such complexity manifests as larger logic trees, more sophisticated data-integration techniques, better understanding of input data uncertainties, and the computational capacity to undertake high-resolution simulations (e.g., CyberShake) and inversions for earthquake rate models (e.g. UCERF3). We invite papers on topics that include uncertainty analysis in PSHA, new approaches to gridded, area, and finite-fault source representations, logic-tree analysis and trimming, deaggregation, site-specific methodologies, computational algorithms, simulation based methods, urban hazard maps, new source and ground motion models, and other research or approaches related to PSHA.
Since the power-law scaling of the earthquake-size distribution has been documented for the first time by Ishimoto and Iida in 1939, 75 years ago, it has become most commonly characterized by the b-value in logN=a-bM, published in 1944 by Gutenberg and Richter and cited more than 1500 times since then. A multitude of studies have since been devoted to uncover the nature of b: From suggestions of being universal and unity to reports of significant spatial and temporal variation. From global catalogs to local microseismicity and acoustic emissions in laboratory experiments. From natural earthquakes to induced seismicity. From statistical robustness analysis to b-value imaging and physical interpretation. Beyond these aspects, the b-value is frequently used in seismic hazard analysis for linking the observed smaller to the infrequent larger event rates, and an improved understanding of its properties and meaning is crucial to advance future seismic hazard assessment. Recent years have offered exciting new insights, according to which the observed natural b-value variability can be related to physical properties of the crust, in particular its stress distribution, such as has been suggested from lab experiments for decades. We invite b-value related contributions from all scales – laboratory, induced and natural seismicity – addressing variability or stability in space and through time. We would like to discuss statistical requirements, appropriate techniques and uncertainty treatment; we are particularly interested in approaches of physical interpretation – (what) can we learn from b-value analysis about the physics of the crust and spatiotemporal earthquake potential? We also invite studies from different backgrounds that face similar analysis challenges or reveal related characteristics, such as strong along fault heterogeneity – do they offer new correlation prospects with b? Or what about b-values in the physical earthquake simulator world? We aim for a forum to discuss the state-of-the-art in b-value analysis and its impact and outline future challenges and opportunities.
There is a growing trend across scientific disciplines for citizens to aid scientific research and monitoring. In seismology, citizens now contribute both actively and passively to the collection and analysis of seismic data. These efforts include documenting macroseismic effects on a scale not imaginable before the advent of the Internet, contributing to early detection of significant earthquakes, and hosting of seismometers of various types. Citizen seismology clearly offers enormous potential to not only contribute to scientific research but also to push scientists to better understand and respond to public demands and expectations after natural disasters. In this session we invite contributions that focus on quantitative analysis of macroseismic data from both historical and instrumental earthquakes as well as papers that cover technical aspects of citizen science, ways to better engage with citizens,and other applications.
Topographic features can produce significant stress in the lithosphere. These topographic stresses can be on the order of inferred stress drops in earthquakes, raising the possibility that they may affect the earthquake processes. In the upper crust, the topographic stresses can be quite heterogeneous, resulting in stress heterogeneities of both fault shear and normal stresses even if the background tectonic stress is relatively smooth. Dynamic earthquake simulations have shown that stress heterogeneities on the order of several MPa or more have a strong effect on the earthquake rupture process. Additionally, flexure and isostatic rebound due to changes in water, ice or sediment loads on the Earth’s surface can affect fault behavior over many earthquake cycles, and in some cases may trigger earthquakes on relatively short timescales. We call for theoretical or empirical research on the interactions of topography and surface loads with earthquake behavior. We particularly welcome submissions addressing the following broad topics: Models of dynamic earthquake rupture with heterogeneous pre-earthquake fault normal and shear stress; Constraints on the stress evolution throughout an earthquake, including both stress drop and final post-earthquake stress; relationship of topographic stresses and rupture in an individual earthquake; Relationship between topography and location or style of faulting; Modulation of fault activity due to changes in surface loads; and Measurements and quantitative estimates of stresses near faults.
In this session, we investigate the coupling of explosive energy to the radiated seismic wave field. Integration of detailed site setting, material characterization and modeling efforts for understanding explosive sources is critical for nuclear test monitoring and verification. In order to relate near field explosive source phenomenology with far-field observations in areas where characterization data may not exist, well-constrained input and validation from materials testing, structural analysis, field observations, overhead imagery, subsurface feature detection, first-principle calculations, and source-to-receiver modeling are required. These approaches must then be translated into useful, transportable methods for the verification community to characterize the source and quantify uncertainties. We invite contributions from all research focus areas and technologies that meld efforts described above.
Recent damaging earthquakes in Oklahoma, Colorado, and Arkansas have renewed interest in induced seismicity. Across the central and eastern United States, the seismicity rate has doubled over the past 11 years. This rate change can largely be attributed to earthquakes induced by fluid injection associated with oil and gas production. Given the occurrence of damaging earthquakes and the large increase in seismicity rate observed in the United States, it is of critical importance that induced earthquakes are better understood such that their hazards may be mitigated. Topics of interest to address these issues include: the causes of fluid-injection induced earthquakes; methods to distinguish natural and induced earthquakes; why some wells trigger earthquakes, but the vast majority of wells do not; how fluid-injection induced earthquakes may be controlled; and how to estimate the hazard associated with already developed and new fluid injection fields. We invite papers on all forms of induced seismicity but particularly those associated with waste water-injection, geothermal production, carbon sequestration, and hydraulic fracturing. Papers from industry are particularly welcome to better inform the research community on the state of knowledge and practices within the community. As part of this session, a roundtable discussion will be held to discuss (1) the factors influencing induced seismicity, (2) the uncertainties in characterizing induced seismicity, (3) strategies to control induced seismicity, and (4) methods to characterize the earthquake hazards associated with fluid injection.
Large earthquakes have continued to garner global attention in 2013. Significant events have struck Iran (Khash, April 2013, Mw7.7); China (Lushan, April 2013, Mw6.6); Russia (Okhotsk, May 2013, Mw8.3); New Zealand (Blenheim, August 2013, two Mw 6.5 earthquakes); Pakistan (Awaran, September 2013, Mw7.7); and the Philippines (Bohol, October 2013, Mw7.1), all in the past half-year. Further large and damaging events may also occur over the following six months. Studies of these earthquakes are important not only from a societal perspective – several of these events each caused hundreds of fatalities, and significant economic losses – but also seismologically – the Sea of Okhotsk earthquake was the largest deep earthquake ever recorded, and the Pakistan earthquake was another example of a large continental event involving complex slip on multiple fault structures. We welcome analyses of these earthquakes, from teleseismic to regional studies using seismic data, to co- and post-seismic GPS and InSAR analyses, to studies of the societal and economic impact of such events. Research that tackles event characterization from a multi-disciplinary approach is particularly encouraged.
Multiparameter observations (e. g., seismic, acoustic, video, etc.) of natural and man made explosions have the potential to provide important details of source time functions and coupling of seismoacoustic waves. For example, a series of recent studies have observed signatures of rapid ground deformation, distortions due to topographic effects, production of nonlinear acoustic waves, and complex seismoacoustic partitioning during explosions. Understanding these relationships is important for characterizing geophysical phenomena in the atmosphere and the solid earth. Such detailed knowledge is also critical in volcano and nuclear explosion monitoring. We encourage contributions that describe extensions of our current seismoacoustic monitoring capabilities with innovative technologies, network configurations, and observational methods.
Faults are complex zones of highly deformed rock containing hydro-mechanical heterogeneities from the grain to plate boundary scale. These heterogeneities influence frictional properties of faults and control the dynamics of slip instabilities from episodic tremor and slow slip to large earthquake ruptures. Rupture nucleation, propagation and arrest may be affected by variations in intrinsic fault characteristics, for example, fault hydrology, geometry and structure. While fault structure has been studied extensively on exhumed faults much remains unknown about fault structure at depth and its interplay with earthquake ruptures. Can fault heterogeneity limit the length of earthquake ruptures and control nucleation points of large earthquakes? Can fault heterogeneity explain the large diversity of slip behavior (from exotic slow events to large earthquakes) observed along faults? How do ruptures depend on faults characteristics, e.g., roughness, pore pressure and frictional properties? How does deformation localize within faults and is the degree of localization a function of fault lithology and age? How does fault heterogeneity evolve with successive rupture events? How are off-fault damage zones created? What is the contribution of dynamically vs. statically created damage? How is fault heterogeneity connected to the creation of fore and aftershocks? To encourage an exchange on some of these questions, we solicit contributions from observational, numerical and experimental studies of fault structure, heterogeneity and implications for earthquake ruptures.
Thomas H. W. Goebel
Emerging time-lapse geophysical methods offer the opportunity to observe active geologic systems as they evolve. For example, examination of the coda of repeating earthquakes and ambient seismic wavefields have allowed for the detection of small temporal changes in velocity at active volcanoes and fault zones. Other recently discovered observables show promise for being even more sensitive measures of small changes. These dynamic methods of observation can provide insight into changing fault zone properties during the seismic cycle or the evolution of a volcanic eruption. In this session, we welcome studies that employ time-lapse geophysical methods to monitor active geologic systems. What can such methods tell us about these systems and how can they be efficiently transferred into tools for routine monitoring?
Silvio de Angelis
Seismology has long been the primary means through which to study and monitor the movement of magma and other fluids in active volcanic systems. However, despite decades of seismic monitoring at volcanoes, the ascent of magma and the circulation of fluids within volcanic systems, and how these phenomena are reflected in geophysical signals, remain poorly understood. In recent decades, improvements in instrumentation and processing techniques have led to the development of additional geophysical tools capable of tracking fluid movement, including infrasound, high-rate GPS, InSAR and gravity. These tools, often used in concert with seismological techniques, have brought forth many new insights that were previously unknown. We seek submissions highlighting interdisciplinary geophysical monitoring and study of fluid movement in active volcanoes and geothermal systems. We encourage contributions that emphasize advances in numerical modeling, feature new instrumentation or analytical methods, and/or provide new insights into the physical processes controlling fluid movement.
The William B. Joyner Memorial Lectures were established by the Seismological Society of America (SSA) in cooperation with the Earthquake Engineering Research Institute (EERI) to honor Bill Joyner's distinguished career at the U.S. Geological Survey and his abiding commitment to the exchange of information at the interface of earthquake science and earthquake engineering, so to keep society safer from earthquakes. Joyner Lecturers are chosen on the basis of their work at this interface, whether they are contributions from earthquake science to earthquake engineering or from earthquake engineering to earthquake science. For more information on the Joyner Lectures see this web page.
This session highlights recent advances in earthquake physics and the interrelationships between earthquakes in a particular region. Topics include earthquake clustering, time-dependent forecasting, scaling relationships, stress drop studies, and others.
Modern earthquake location and monitoring techniques have revolutionized seismology, allowing better images of fault structure, stress, and time-dependent frictional properties. This session explores new techniques and results in this important seismological field.
This session consists of papers on new developments in seismic and GPS networks and data centers. These include reports on new types of instrumentation, upgrades of existing seismic networks, and data processing. Great data is of no value unless it can get to the user. The session also includes new developments in serving data to the earthquake community.
A better evaluation and understanding of earthquake hazards can only come from regional studies of seismicity and active deformation. This session presents research on regional seismicity from around the globe.
Processes that lead to seismicity are diverse and varied from common slip of rocks along faults to ice quakes to fluid-induced seismicity. This session presents research on processes leading to seismicity.
A primary incentive to understanding earthquakes is in evaluating the hazard. This session includes presentations on a diverse array of hazard analysis, from precariously balanced rocks, to nuclear plants, to the L'Aquilla trial, and the utility of response spectra.