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SSA 2012 Annual Meeting


The following sessions have been organized for the 2012 Annual Meeting program. Click any session name to view the schedule and list of abstracts for that session.

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Use the "hashtag" (beginning with a “#” symbol) below each session’s title to search and tweet about your special session!

Advances in Rapid Earthquake and Tsunami Detection and Modeling using Geodetic and Seismic Data

Follow on Twitter: #SSA2012_AR

Experience with the great earthquakes and ensuing tsunamis of the last decade has shown that traditional seismic monitoring can be greatly improved in its ability to rapidly estimate accurate earthquake magnitude and fault slip parameters by the addition of real-time GPS measurements of static and dynamic seismic deformation. This session focuses on the exploitation of near-field real-time GPS data alone or in combination with seismic data to directly estimate displacements with sufficient accuracy to significantly improve the timeliness of earthquake parameter estimation, thereby also enhancing tsunami early warning and modeling. We welcome contributions on earthquake and tsunami early warning approaches for large/great earthquakes, scaling relationships for estimating earthquake magnitude, rapid centroid and moment tensor solutions, near-real-time finite fault slip inversions and tsunami modeling. Also of interest are preparations for monitoring expected large events in Western North America, including the Cascadia megathrust, the San Andreas fault, and the Mexican subduction zone.

Session Chairs

Yehuda Bock <ybock [at] ucsd [dot] edu>

Shri Krishna Singh <krishnamex [at] yahoo [dot] com>

Timothy Melbourne <tim [at] Geology [dot] cwu [dot] EDU>

Challenging the Idea of Seismic Coupling along Subduction Zones: Chile, Sumatra, Tohoku…What’s next?

Follow on Twitter: #SSA2012_CI

Over the last decade the occurrence of a significant number of subduction related mega-events (Sumatra-Andaman Islands, Tohoku-Oki, Alaska) has openly questioned the state of knowledge about the lithospheric processes behind these earthquakes. After Sumatra earthquake, the seismological model supporting strong coupling between the convergence rate and the age of the subducting lithosphere has been challenged. In the Cascadia subduction zone, an increasing number of paleoseismic data available is being used to re-evaluate historical events, leading to new estimates of its behavior. After March 2011 the question is Will Tohoku earthquake change the way we think about seismic coupling along subduction zones and the maximum expected magnitude? In this session we invite studies related to the mapping of seismic coupling along subduction zones considering the spatiotemporal variability of seismic energy release, including time periods and sub-regions for which the plate interface appears to be locked. Are there any specific plate boundaries where a re-evaluation of the maximum expected magnitude is more critical than ever? Are seismic hazard estimates that assume most of a subduction boundary is aseismic still viable? This session also aims to re-evaluate seismological data using either relocated catalogs or re-determined epicenters of important mega- events which will aid future studies of seismic coupling. The overall target of this session would be to promote the discussion about new directions in research related with earthquake forecasting and monitoring along subduction zones.

Session Chairs

Margarita Segou <msegkou [at] usgs [dot] gov>

William Ellsworth <ellsworth [at] usgs [dot] gov>

Continental Lithospheric Structure and Tectonics of Central North America

Follow on Twitter: #SSA2012_CL

As USArray Transportable Array moves into the continental interior, new insights are being made into the lithospheric and deep seismic structure of North America. Delineating crustal and mantle interfaces, strength heterogeneities, velocity gradients, and structure can provide important constraints for the formation and composition of the continents and evolution of cratons. Mapping of seismotectonic structures may help understand the interaction of different tectonic provinces within central North America, and their role in the seismogenic processes in intraplate regions. We seek contributions from Earthscope or other projects on the North American continental lithosphere and upper mantle structure that include passive and active source seismology, geodynamic modeling, tectonics, geodesy, and other integrated multidisciplinary studies.

Session Chairs

Meghan S. Miller <msmiller [at] usc [dot] edu>

M. Beatrice Magnani <mmagnani [at] memphis [dot] edu>

Luciana Astiz <lastiz [at] ucsd [dot] edu>

Debating Fault Model Input Data

Follow on Twitter: #SSA2012_DF

Stochastic and physics-based models of fault systems have been developed in an attempt to provide reliable rules for models of seismogenic regions that can have a predictive power. Whether it be the rate and maximum magnitude of aftershocks, the probability for a rupture to jump from a fault segment to another, or the recurrence behavior of large events on simple faults, our predictions all depend on noisy and potentially incomplete datasets. This affects both empirical, stochastic,and physics-based models. In this session, we encourage modelers to choose first order, general rules about slip distributions, ground motion, and other parameters that arise from their model outputs, and discuss which subset of the input data they are most sensitive to. We also encourage data providers to explain how well these critical data are known and what amount ofcomplexity or variability (in space or time) we could expect these properties to exhibit, based on their observations. Finally, we welcome contributions from modelers and statisticians on how the data should be reported to be most useful, and from data gatherers on how their data should be used. We welcome contributors from deterministic and stochastic modeling, probabilistic modeling,seismology, geodesy, earthquake geology (including geomorphology, paleoseismology, etc), fault and rock mechanics.

Session Chairs

Delphine Fitzenz <delphine [at] uevora [dot] pt>

Andrew Michael <michael [at] usgs [dot] gov>

Deformation Processes and Properties of the San Jacinto Fault Zone

Follow on Twitter: #SSA2012_DP

The San Jacinto fault is one of the most active branches of the San Andreas system in southern California, and it consists of multiple segments that exhibit considerably different properties and behaviors both at the surface and at depth. As such, it provides an excellent natural laboratory for studying the mechanics, architecture and evolutionary processes of a young transform plate boundary system. This session will provide a platform for discussing these topics based on in-situ geological, geodetic and seismological data from the San Jacinto fault zone, along with related laboratory and theoretical results.

Session Chairs

Yehuda Ben-Zion <benzion [at] usc [dot] edu>

Tom Rockwell <trockwell [at] geology [dot] sdsu [dot] edu >

Frank Vernon <vernon [at] epicenter [dot] ucsd [dot] edu>

Detecting, Modeling and Predicting the Seismic Source

Follow on Twitter: #SSA2012_DM

The seismic source has a controlling effect on ground motion and thus seismic hazard, but it is also the most uncertain and difficult to characterize.  This session combines seismic observations, laboratory work, and modeling studies to better estimate the size, potential slip patterns, and timing of earthquakes.

Session Chair

Yoshihiro Kaneko<ykaneko [at] ucsd [dot] edu>

Dynamics of Seismicity Beyond Universal Scaling Laws

Follow on Twitter: #SSA2012_DS

Finding genuine aspects of seismicity that reflect local properties of faults or the crust, beyond the average regional Gutenberg-Richter magnitude distribution and Omori-Utsu aftershocks decay, is a highly challenging problem because of the inherent complexity of the earthquake process combined with the limited and noisy available data. Using large spatial domains increases the amount of data, but may suppress important local properties of seismicity. This session will focus on statistical features of seismicity specific to various sub-regions, and their relations to independent geophysical observations (e.g.,seismic velocity images, heat flow). Examples include space-time variations of foreshock/aftershock clustering and productivity, bursts of activity, swarms, periodic seismicity, triggering and other patterns that go beyond the classical power laws.

Session Chairs

Yehuda Ben-Zion <benzion [at] usc [dot] edu>

Ilya Zaliapin <zal [at] unr [dot] edu>

Earthquake Debates

Debate #1 - Concept of Segmentation

Follow on Twitter: #SSA2012_ED1

Do known faults and their segmentation tell us anything about the location and extent of large earthquakes?  Did the Tohoku earthquake kill the concept of  segmentation?

The Tohoku earthquake and the Canterbury earthquake sequence stimulated discussions whether or not the concept of fault segments is valid and useful.  Segments seems clearly visible from a geological point of view.  Microseismicity often seems to ignore segment boundaries. Earthquake rupture forecasts are taking into account the probabilities of rupturing through segment boundaries and even from fault to fault. How valid and useful is the concept of segments? Are segments limited by only apparent boundaries or are these boundaries physical? Is the knowledge of segments increasing our abilities to forecast the size of earthquakes? Was Tohoku an exception or the rule? We solicit presentations that contribute to this discussion and try to shed light on this open question.

Speakers are by invitation only. However, the session is open to submissions for poster presentations. Some poster presenters may be asked to join a panel during the discussion after the oral debate.

Debate #2 - PSHA Methodology

Follow on Twitter: #SSA2012_ED2

PSHA has been an invaluable contribution to how seismic hazard has been done in recent decades, but is it nearing its maximum potential?  Will future iterations be able to make more than minor improvements or should we be putting more effort into investigating alternative methodologies?

PSHA is the gold standard in computing seismic hazard. It is used worldwide on different scales, from global to site-specific assessments. Its results are directly used for seismic risk assessment. But can the large uncertainties be overcome within its framework? Can other methodologies provide more reliable and useful assessments? Did the Tohoku earthquake reveal shortcomings of PSHA that are intrinsic to the method? We solicit presentations that discuss the strengths and weaknesses of PSHA or that show other, maybe more promising, ways for hazard assessments.

Session Chairs

Danijel Schorlemmer <ds [at] gfz-potsdam [dot] de>

David Jackson <djackson [at] ucla [dot] edu>

Matt C. Gerstenberger <m [dot] gerstenberger [at] gns [dot] cri [dot] nz>

Matthias Holschneider <hols [at] math [dot] uni-potsdam [dot] de>

Earthquake Location and Monitoring

Follow on Twitter: #SSA2012_EL

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.

Session Chair

Felix Waldhauser <felixw [at] ldeo [dot] columbia [dot] edu>

Earthquake Strong-Motion Modeling - Posters only

Follow on Twitter: #SSA2012_ES

Data- and simulation-based models for strong ground motion are key tools for seismologists who are interested in characterizing seismic hazard.  Such studies require an understanding source, path, and site effects.  This session explores current research in ground motion modeling, using historic data as well as faulting simulations.

Earthquakes and Tsunamis at Coastal Archaeological Sites

Follow on Twitter: #SSA2012_ET

The study of earthquakes and tsunamis at coastal archaeological sites provides a view into their magnitude, timing, and severity. Earthquake and tsunami risk is particularly prevalent on the dynamic and sensitive coastal zones. Today, as in the past, people are drawn to this dynamic niche due to its broad resource base, often temperate climate, and access to trade routes. While the effects of gradual, annual, decadal, or millennial changes might be possible to mitigate, punctuated high energy events such as earthquakes and tsunamis can alter the coastline permanently in a matter of minutes to days, impacting the livelihoods of residents, damaging infrastructure, and remolding and modifying the coastline. Therefore, it is crucial to be well informed of past events as a reference for advising coastal management strategies and disaster preparation and response guidelines. Reconstructing past earthquake and tsunami events with the use of information from coastal archaeological sites can provide a more complete and informative database of tsunami and earthquake history. This session explores the records of earthquakes and tsunamis at coastal archaeological sites and methods for quantifying tsunami and seismic hazard parameters from archaeological data.

Session Chairs

Manuel Sintubin <manuel [dot] sintubin [at] ees [dot] kuleuven [dot] be >

Beverly N. Goodman Tchernov <goodmanbeverly [at] gmail [dot] com >

Tina M. Niemi <NiemiT [at] umkc [dot] edu>

El Mayor-Cucapah, Baja California M7.2 Earthquake of 4 April 2010: Research Results and Lessons

Follow on Twitter: #SSA2012_EC

El Mayor-Cucapah earthquake on 4 April 2010 occurred between the Laguna Salada rift basin and the Pacific-North America plate boundary. This event has been one of the strongest earthquakes recorded on southern California and northern Baja California. This earthquake has motivated several multidisciplinary studies, on both sides of the international border, to understand the seismotectonics of the region, the rupture process, and other geophysical phenomena observed during this important earthquake sequence. We invite contributions from all aspects of geophysical studies carried out in the epicentral region of El Mayor-Cucapah seismic sequence including: earthquake relocation, strong ground motion, building damage, site amplification, ground failure, surface faulting, GPS, InSar and other geophysical measurements related with the seismic zone.

Session Chairs

Victor Wong <vwong [at] cicese [dot] mx>

Raul Castro <raul [at] cicese [dot] mx>

Ground Motion Prediction Equations and Earthquake Site Response

Follow on Twitter: #SSA2012_GM

A new generation of empirically determined attenuation equations, which describe peak ground accelerations (PGA) and peak ground velocity (PGV) as a function of magnitude and distance, are presented together with methods to estimate site response.

Session Chair

Alan Yong <yong [at] usgs [dot] gov

Macroseismic Effects in Recent and Ancient Earthquakes and their Relationship to Ground Motion Parameters

Follow on Twitter: #SSA2012_ME

Man-made constructions exhibit macroseismic effects from earthquakes that are of primary interest for seismologists, civil engineers and, occasionally, archaeologists. In its infancy, modern seismology made use these effects to not only scale the strength of an earthquake but also to deduce source parameters such as the epicenter. Specifically, objects of investigation included such toppled and rotated objects as tombstones, simply structured monuments, and columns. While present-day earthquake locations are achieved by seismic measurements, the link between site-specific ground motions and damaged constructions is still of great importance. The correlative factors, however, are even today not always fully understood. In order to interpret effects of ancient earthquakes on simple structures and buildings, instrumentally observed earthquakes producing similar macroseismic effects offer a chance to refine methods of back calculation of ground motion parameters. The goal of this session is to bring together strong motion and engineering seismologists, civil engineers, geologists, archaeologically interested seismologists and archaeologists to discuss possibilities and limitations of the deduction of ground motion parameters from macroseismic effects. This includes also the study of geological and geomorphologic factors to local rotations. Contributions to methodo logical developments are encouraged as well as presentations of field cases and data collections.

Session Chairs

Klaus -G. Hinzen <hinzen [at] uni-koeln [dot] de>

Luigi Cucci <luigi [dot] cucci [at] ingv [dot] it>

Mariano Garcia-Fernandez <mgarcia [at] mncn [dot] csic [dot] es>

Andrea Tertulliani <tertul [at] ingv [dot] it>

Neotectonics, Fault Geology and Paleoseismic Studies - Posters only

Follow on Twitter: #SSA2012_NF

Studies of fault zones and new fault structure facilitate better estimates of slip rates and improve the evaluation of seismic hazard New paleoseismic trenches reveal significant fault offsets generated by historical earthquakes. This session focuses on studies of neo-tectonics and fault geology in seismically active regions.

Non-Volcanic Tremor, Slow-slip Events and Remote Triggering

Follow on Twitter: #SSA2012_NV

Episodes of non-volcanic tremors recorded in different regions suggest that they may be associated with slow-slip events. New results and models that explain these observations together with new studies of remote triggering are presented in this session.

Session Chair

Michel Campillo <Michel.Campillo [at] obs [dot] ujf-grenoble [dot] fr>

Numerical Modeling of Earthquake Motion and Seismic Wave Propagation

Follow on Twitter: #SSA2012_NM

Numerical modeling has been and will likely remain an important tool for investigating rupture propagation, earthquake ground motion and seismic wave propagation. Refinements and innovations in numerical modeling are being driven by the demands to interpret increasing volumes of seismic data; the scientific and engineering requirements to reproduce and predict seismic motion in realistically complex media over a broad frequency band; and the rapid development of computer resources. Advancements (e.g., in modeling capabilities, accuracy levels, and computational efficiency) are spurred when there is joint involvement of, and interactions among, mathematical and computational scientists, algorithm developers, and those applying the methods. We invite contributions focused on development, verification and validation of the numerical-modeling methods, and on methodologically important applications. Contributions on the analysis of methods, development of fast algorithms, GPU applications, large-scale simulations, non-linear behavior, multiscale problems, and confrontation of methods with data are especially encouraged.

Session Chairs

Emmanuel Chaljub <emmanuel [dot] chaljub [at] ujf-grenoble [dot] fr>

Steven Day <day [at] moho [dot] sdsu [dot] edu>

Peter Moczo <moczo [at] fmph [dot] uniba [dot] sk>

Physics in Seismology: The Legacy of Leon Knopoff

Follow on Twitter: #SSA2012_LK

This special session solicits papers honoring the scientific accomplishments of Leon Knopoff (1925-2011) by demonstrating their impact on modern seismology. Knopoff introduced a wide range of physics topics to seismology, laying down the foundation for much current work. Papers that demonstrate the Knopoff heritage in recent developments in nonlinear earthquake dynamics, earthquake statistics, theoretical elastodynamics, wave propagation, and tectonophysics would be particularly relevant. Knopoff ‘s work involved representation theory, spring-block sliders, self-organized criticality, earthquake statistics, stochastic branching models of the source, physics of the ETAS model and Omori laws, Q, and application of condensed matter physics to seismology. The objective of the session is to highlight how this type of scientific approach can serve as an example for future work.

Session Chairs

Paul Davis <pdavis [at] ess [dot] ucla [dot] edu>

Freeman Gilbert <fgilbert [at] ucsd [dot] edu>

David Jackson <david [dot] d [dot] jackson [at] ucla [dot] edu>

Thomas Jordan <tjordan [at] usc [dot] edu>

Probabilistic Fault Displacement Hazard Analysis

Follow on Twitter: #SSA2012_PF

Propagation of fault rupture to the ground surface can result in disruption of lifelines and damage to engineered features. Forecasting potential surface fault rupture displacement using probabilistic methods has become more tractable in the last decade. This session brings together speakers to discuss recent advances in fault displacement hazard analysis on probabilistic methods, statistical models, numerical solutions, and case histories. The goal of this session is to discern where there is agreement and where there is disagreement in probabilistic fault displacement hazard analysis to set the path for future research.

Session Chairs

Robb Moss <rmoss [at] calpoly [dot] edu>

Mark Petersen <mpetersen [at] usgs [dot] gov>

Probabilistic Seismic Hazard Analyses, Models, Maps and Simulations

Follow on Twitter: #SSA2012_PSHA

Probabilistic seismic hazard analyses have become an important tool in the construction of realistic earthquake scenarios for regions of high seismic risk. New models, maps and simulations determined for different regions are presented in this session.

Session Chair

Ivan Wong <ivan [dot] wong [at] urs [dot] com>

Rotations in Strong-motion Seismology

Follow on Twitter: #SSA2012_RS

Significant progress has been made in observing and analyzing rotational ground motions in recent years. Accurate measurements of these additional components of ground motion are especially important in strong-motion seismology and earthquake engineering. Rotational motion and its effects on strong-motion data have been ignored for their much smaller amplitudes than that of the translational motions. However, recent observations from large ground motions suggest that these effects might be underestimated and detailed analyses of these effects are necessary. Rotational components of earthquake ground motion are usually not considered for seismic analysis, design and performance assessment at this time because time-series recordings of these components are rare. A number of procedures have been proposed to extract rotational components of ground motion from translational time series recorded by arrays of closely spaced stations. There are also new sensors capable of recording point rotations, and some of them have already been used in field and laboratory measurements. We invite submission of presentations that document progress in measurement, analysis, application, and theory of rotational strong-motion. We specifically emphasize rotational strong-motions of the order of 10-5 and higher (up to ~ 10-2) rad that can produce significant effect on structures.

Session Chairs

Vladimir Graizer <Vladimir [dot] Graizer [at] nrc [dot] gov>

Maria Todorovska <mtodorov [at] usc [dot] edu>

Seamount Subduction and Earthquakes - Posters only

Follow on Twitter: #SSA2012_SS

Seamounts are ubiquitous topology features, with sizes ranging from a few to tens of kilometers in width and up to several kilometers in height. When they enter subduction zones, they have profound effects on forearc morphology, fault zone structure, material transfer, and earthquake generation. Traditionally, subducting seamounts have often been assumed to cause large megathrust earthquakes; however other studies associate subducted seamounts with weak interplate coupling. Many variables may affect whether seamounts result in relatively strong or weak patches on the plate boundary. A more thorough observational and theoretical investigation of the role of seamounts in seismogenesis is needed. In this session, we solicit contributions on studies of subducting seamounts including, but not limited to, imaging seamounts in subduction zones, modeling the mechanics of seamount subduction, effects of subducting seamount on megathrust earthquake ruptures, and indicators of tectonic erosion and forearc deformation caused by seamount subduction.

Session Chairs

Hongfeng Yang <hyang [at] whoi [dot] edu>

Susan Bilek <sbilek [at] nmt [dot] edu>

Anne Trehu <trehu [at] coas [dot] oregonstate [dot] edu>

Kelin Wang <Kelin [dot] Wang [at] NRCan-RNCan [dot] gc [dot] ca>

Seismic Imaging: Recent Advancement and Future Directions

Follow on Twitter: #SSA2012_SI

Seismic imaging is a powerful tool for geophysicists to probe the Earth’s interior. The demand for higher resolution and broader range of applications is rapidly increasing. This session welcomes contributions from seismic imaging in various scales and application arenas, with special emphasis on recent advances and future directions. Examples may include innovations and advances in 3D traveltime tomography, waveform tomography, receiver function mapping, surface wave inversion, and joint inversion of multiple geophysical observations. We also encourage case study papers using seismic imaging to solve real problems. Discussions on the pitfalls, limitations, and artifacts of common seismic imaging methods and potential remedies are most welcomed.

Session Chairs

Youshun Sun <youshun [at] mit [dot] edu>

Michael Begnaud <mbegnaud [at] lanl [dot] gov>

Sidao Ni <sdni [at] whigg [dot] ac [dot] cn>

Junmeng Zhao <zhaojm [at] itpcas [dot] ac [dot] cn>

Seismicity in Volcanic Environments

Follow on Twitter: #SSA2012_SV

Volcano seismicity takes a variety of forms including high- and low-frequency events, tremor, and explosions. These signals are used directly in volcano monitoring and risk mitigation and provide a method for studying the physics of volcanic environments and eruptions. Recent advances in seismic instrumentation, multi-sensor studies (e.g., infrasound, doppler, video), and numerical modeling have improved our ability to interpret seismic signals recorded in volcanic environments. These studies demonstrate the variety of physical processes that may be responsible for the generation of these signals. We invite contributions utilizing observational, theoretical, laboratory and/or modeling techniques, particularly those connecting seismic signals to physical processes in volcanic environments.

Session Chairs

Darcy Ogden <dogden [at] ucsd [dot] edu>

Eric Dunham <edunham [at] stanford [dot] edu>

Sensors and Software Techniques - Posters only

Follow on Twitter: #SSA2012_SS

Seismic hardware and software play a key role in earthquake monitoring and analysis.  This session explores recent advancements in this important technical field, with its implications for earthquake science.

Structure Models, Wavespeed and Attenuation

Follow on Twitter: #SSA2012_SW

The determination of accurate velocity structures using P and S waves is essential to improving earthquake locations, ground motion analyses and to understanding local and regional tectonic settings. This session presents new structure models based on wave velocities and seismic attenuation studies.

Session Chair

Vera Schulte <vera [dot] schulte [at] gmail [dot] com>

Surface Deformation and Geodetic Techniques - Posters only

Follow on Twitter: #SSA2012_SD

Recent advances in geodetic techniques such as InSAR and GPS allow researchers to better determine subsurface fault structure and interseismic deformation, as well as coseismic properties of earthquakes.  This session brings together presentations that use these techniques to better characterize deformation in various potentially seismically active regions.

The 11 March 2011 Tohoku, Japan Earthquake:  Observations and Models - Posters only

Follow on Twitter: #SSA2012_Tohuku

The 11 March 2011 Tohoku, Japan Earthquake produced a huge tsunami, as well as some of the highest ground motion ever recorded and the some of the highest fault slip ever inferred.  This session brings together observations of and models to reach a better understanding of this important event.

The 23 October 2011 Van, Turkey Earthquake:  Observations and Implications

Follow on Twitter: #SSA2012_VA

The October 23, 2011, Mw7.2 Van earthquake in eastern Turkey is the latest of a number of recent large (M~7) earthquakes to cause many deaths and significant damage in a continental setting. This earthquake occurred in a tectonically complex area of convergence and right-lateral shear between Arabia and Eurasia, far from the recognized major plate boundaries, and with the relatively simple strike-slip systems of the North and East Anatolian Faults located well to the west. This session will focus on scientific, technical and social studies of the earthquake's immediate and long-term effects. We welcome contributions from the fields of seismology, geodesy, geology, engineering, and governmental and non-governmental response that provide insights into all aspects of the earthquake cycle in the area, the regional tectonics and structure, and the local impacts of the earthquake and its aftershocks. Studies that highlight comparisons to, or lessons learned from, other similar major earthquakes in the last few years, for example the Haiti and Christchurch earthquakes, and that discuss implications for analogous areas of oblique convergence in California and elsewhere are also encouraged.

Session Chairs

Gareth Funning <gareth [at] ucr [dot] edu>

Mike Floyd <mfloyd [at] mit [dot] edu>

Semih Ergintav <semih [dot] ergintav [at] mam [dot] gov [dot] tr>

Tying Nearfield Phenomenology to Farfield Measurements: Explosion Source Physics and Energy Propagation Through Complex Media

Follow on Twitter: #SSA2012_TN

A key to improved explosion source characterization is a physical basis relating nearfield phenomenology to remote/farfield observations. Developing a physical basis requires a comprehensive research program with at least three focus areas: field experiments, first-principle calculations, and source-to-receiver modeling. Core questions revolve around the manifestations of multiple length- and time-scale source and path phenomena in band-limited recordings acquired at distant stations. To be relevant, the results of studies of such phenomena must be translated into useful methods for the verification community to characterize the source and quantify uncertainties. The theme of this session is the identification of important source and propagation phenomena, their manifestations in remote/farfield observations, and the construction of physical basis models for characterizing the source and quantifying errors. We invite contributions from all research focus areas and technologies with emphasis on laying a physical basis for yield estimation and source-type discrimination.

Session Chairs

Robert Abbott <reabbot [at] sandia [dot] gov>

Tarabay Antoun <antoun1 [at] llnl [dot] gov>

Howard Patton <patton [at] lanl [dot] gov>

Chandan Saikia <csaikia [at] aftac [dot] gov>

Catherine Snelson <snelsocm [at] nv [dot] doe [dot] gov>

Uncertainty in the Estimation of Earthquake Hazard

Follow on Twitter: #SSA2012_UE

The primary focus of National Seismic Hazard Mapping Project (NSHMP) is to develop the mean hazard. The project considers explicitly both the aleatory (natural variability) and the epistemic (modeling) uncertainty. Epistemic uncertainty is typically considered in the hazard analysis by using logic trees. The hazard curve from each of the possible branches defines the uncertainty in the hazard. Since the primary objective of NSHMP is to develop the mean hazard curve, sometimes some of the logic tree branches are ignored because of little impact of that branch on the estimation of mean hazard. But those branches can be important in the calculation of uncertainty in the hazard. The epistemic uncertainty in the hazard is expected to be lower in California where the amount of information is relatively high from frequent earthquake events compared to uncertainties in New Madrid or Charleston area where limited information is available from fewer events. The uncertainty in hazard plays a significant role in assessing earthquake risks, e.g., for assessing uncertainty in risk-targeted ground motion for designing buildings, or for assessing uncertainty in monetary losses at different return periods for insurance companies. We plan to explore the issue of hazard uncertainty in the upcoming NSHMP update. This session will focus on approaches for quantifying uncertainties, guidance for the treatment of uncertainties and quantification of the uncertainties in the hazard parameters (e.g., b-values), components (e.g., deformation model), and overall model. We invite papers focusing on how to assess uncertainties on inputs to the hazard model and on global examples of hazard and risk uncertainties.

Session Chairs

Nilesh Shome <nilesh [dot] shome [at] rms [dot] com>

Mark D. Petersen <mpetersen [at] usgs [dot] gov>

US-China Collaborations in Seismological and Earthquake Studies

Follow on Twitter: #SSA2012_UC

China is an important natural laboratory for seismological and earthquake studies. From the rise of the Tibetan Plateau and the Tianshan Mountains to extension and volcanism in North China, China is one of the best places to study continental collision and diffusive continental tectonics. With frequent devastating earthquakes and more than 2000 years of historic earthquake records, China is also a key test bed for earthquake models and hypotheses. US and Chinese scientists have a long tradition of collaboration in these studies, which have seen a great acceleration in the past two decades, fueled in part by China’s sharp increase in funding basic science research. The aim of this session is to provide a stage for scientists from both countries and others working on seismotectonics and earthquakes in China to share their results, discuss common problems, and explore future opportunities for collaborations.

Session Chairs

Mian Liu <lium [at] missouri [dot] edu>

Randy Keller <grkeller [at] ou [dot] edu>

Larry Brown <ldb7 [at] cornell [dot] edu>

Yongshuan (John) Chen <johnyc [at] pku [dot] edu [dot] cn>

Validation of Strong Ground Motion Simulations for Engineering Applications

Follow on Twitter: #SSA2012_VS

Despite the thousands of strong ground motion records readily available online, there remains a shortage of records for large magnitude earthquakes at short distances, not to mention for other specific source, path, and site characteristics. More and more, physics-based and/or stochastic numerical simulations of strong ground motions are able to offer realistic samples of such records, but the simulation models should first be validated against available strong ground motion data. This special session focuses on efforts to statistically validate simulated records for engineering applications. Such applications include nonlinear response history analysis of geotechnical or structural (e.g.,building, bridge) systems for building code or risk assessments, and development of prediction models for ground motion intensity measures (e.g.,spectral acceleration).

Session Chairs

Nicolas Luco <nluco [at] usgs [dot] gov>

Sanaz Rezaeian <srezaeian [at] usgs [dot] gov>

Thomas H. Jordan <tjordan [at] usc [dot] edu>

The M5.8 Central Virginia and the M5.6 Oklahoma Earthquakes of 2011

Follow on Twitter: #SSA2012_VO

Two rare, large, intraplate earthquakes struck the eastern US in 2011. Both events were felt over broad areas in surrounding states, and they produced moderate local damage. For the Virginia earthquake, significant damage occurred 135 km away in Washington D.C. and minor damage 200 km away in Baltimore. Large numbers of portable seismic stations were deployed by several organizations following both main shocks. Both main shocks were followed by vigorous aftershock activity making these two of the best-recorded aftershock sequences in the eastern U.S. Scientific investigations of any aspect of these rare intraplate events are appropriate; including source properties, strong ground motion, attenuation, site amplification, building damage, ground failure, and paleo-seismology.

Session Chairs

Stephen Horton <shorton [at] memphis [dot]edu>

Robert Williams <rawilliams [at] usgs [dot] gov>


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SSA 2013
April 17–19, 2013. Salt Lake City, UT.

Last Modified: 2012 Mar 01