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SSA 2010 Annual Meeting

Special Sessions


Advances in Seismic Hazard Mapping RSS

Recently much progress has been made in developing informative regional seismic hazard maps that incorporate local as well as regional geologic and geotechnical data. These new maps often rely on a probabilistic characterization of hazard to account for uncertainties and have been developed for soil amplification, liquefaction hazard, and seismic slope instabilities. Also, recent applications of remotely sensed data have improved post-event hazard maps. This session will be used to highlight new approaches in both pre-event seismic hazard maps and post-event seismic hazard surveys.

Conveners

  • Laurie G. Baise <laurie [dot] baise [at] tufts [dot] edu>
  • Keith L. Knudsen <keith_knudsen [at] urscorp [dot] com>

At the Interface Between Earthquake Sciences and Earthquake Engineering in the Pacific Northwest RSS

As the Pacific Northwest comes to grips with the destructive potential of the Cascadia subduction zone and as more active crustal faults are identified, particularly in the Puget Sound region, our understanding of seismic hazards has improved. Greater efforts are being made by both the earth science and engineering communities to insure that new and existing critical and important structures and facilities as well ordinary buildings are capable of withstanding this higher level hazard. Examples of these efforts include the continuing evolution of the USGS National Hazard Maps in the Pacific Northwest and two regional seismic hazard studies for dams being conducted in eastern Washington and British Columbia. This session will focus on recent advances in the earthquake sciences and how they have impacted earthquake engineering practices in the Pacific Northwest. Case histories where state-of-the-art knowledge and procedures are implemented are of particular interest to this session.

Conveners

  • Ivan G. Wong <ivan_wong [at] urscorp [dot] com>
  • Arthur D. Frankel <afrankel [at] usgs [dot] gov>

Building Code Uses of Seismic Hazard Data RSS

The SSA statement of purpose includes the objective to “promote public safety by all practical means.” Building codes are one of the most effective means of elevating public safety. This session will focus on the ways in which building code applications use, or could use, seismic hazard data from seismologists and others. Examples include:

  • The use of national and regional/urban probabilistic and deterministic hazard maps to develop maps of ground motion intensities for the design of new structures and/or the evaluation/retrofit of existing structures, including buildings,bridges, dams, etc.;
  • Site-specific hazard analysis for such structures and others (e.g., nuclear power plants);
  • The use of ground motion time histories, whether recorded or simulated; and
  • The incorporation of earthquake effects other than ground motion, such as slope instability, liquefaction, total and differential settlement, surface displacement, etc., into building codes

Contributors to the session are encouraged to either present information on current uses of seismic hazard data in building code applications, or to propose future uses that are in line with the SSA objective to promote public safety by all practical means.

Conveners

  • Nicolas Luco <nluco [at] usgs [dot] gov>
  • Charles A. Kircher <cakircher [at] aol [dot] com>

Characterizing the Next Cascadia Earthquake and Tsunami RSS

New insights into the Holocene rupture history of the Cascadia subduction zone, the structure of its forearc, and episodic tremor and slip events located down-dip of the seismogenic zone are redefining source models aimed at characterizing the next megathrust earthquake and tsunami in the Pacific Northwest. This session will feature new research in the fields of geology, seismology and geodesy that have led to improvements in understanding the seismic potential of the Cascadia megathrust. Of particular interest to this session are studies that provide better constraints on the width of the rupture zone, the magnitude of slip, potential fault segmentation and highlight remaining uncertainties. We also encourage submissions that address how new findings can be used to reduce human losses from future megathrust earthquakes and tsunamis, in particular, assessments of seismic and tsunami hazards for mitigation purposes.

Conveners

  • Rob Witter <rob [dot] witter [at] state [dot] or [dot] us>
  • Chris Goldfinger <gold [at] coas [dot] oregonstate [dot] edu>

Deterministic Simulated Ground Motion Records under ASCE 7-10 as a Bridge Between Geotechnical and Structural Engineering Industry RSS

According to new requirements of the American Society of Civil Engineers Standard (ASCE 7-10 Chapter 21 Site-Specific Ground Motion Procedures for Seismic Design), at least five recorded or simulated horizontal ground motion acceleration time histories shall be selected from events having magnitudes and fault distances that are consistent with those that control the Maximum Considered Earthquake. In some cases (e.g., from M6.0 to M8, less than 5 km from the fault zone) there may not be five sets of recorded ground motions that are appropriate, and simulated ground motion would be needed. Based on analytical and numerical simulation for the earthquake rupture propagations ground-motion modeling methods are being increasingly used to supplement the recorded ground-motion database.  Unfortunately, there is no official procedure to follow for near-field sites (D < 5 km from the fault) and for determining whether facilities and bridges are considered critical or essential. This presents a paradox: the Building Codes and Standard ASCE/SEI 7-10 requires engineers to provide simulation of ground motion records (Chapter 21), but there is no official procedure for accomplishing this at near-field sites. This paradox should be resolved as soon as possible.

We invite papers that focus on simulating ground motions that satisfy ASCE/SEI 7-10 and address one or more of the following aspects: 1) procedures for simulating horizontal-, vertical-, and torsion-component ground-motion records for planar and nonplanar fault topology within 5 km of a fault zone; 2) comparisons of solutions for different deterministic models; 3) procedures for determining site-specific design ground-motion parameters for landslides and slope stability analyses with time history procedures; 4) site-specific design ground-motion parameters for bridges and essential facilities (with time history procedures) located within 5 km of a fault zone.

Conveners

  • Alexander Bykovtsev <bykovtsev1 [at] yahoo [dot] com>
  • Walter Silva <pacificengineering [at] juno [dot] com>

Earthquake Debates RSS

Invited speakers will debate important issues in earthquake science. Such issues include the predictability of earthquakes, the distribution of earthquake sizes on major faults, the role of Coulomb stress change in earthquake triggering, and many others. The predictability debate has been with us for decades and is based on many of the contentious issues debated in this session. Speakers will debate what earthquake prediction really means, how it can be evaluated, and whether it is realistic for scientists to promise progress to funding agencies or the public. The issue of earthquake size is often distilled into two limiting hypotheses: characteristic or Gutenberg-Richter distribution. Does Gutenberg-Richter behavior in a large region imply similar behavior on individual faults, and how do we decide when earthquakes are on individual faults anyway? Earthquakes and stress must (?) influence each other, but how? Do static effects of large earthquakes cause Coulomb stress shadows and bright spots, or do dynamic effects dominate earthquake triggering, or something else? Other issues like earthquake periodicity, limits on earthquake size, precarious rocks as seismometers, and limits on strong ground motion are equally contentious.

Conveners

  • Danijel Schorlemmer <ds [at] usc [dot] edu>
  • David D. Jackson <djackson [at] ess [dot] ucla [dot] edu>
  • Warner Marzocchi <marzocchi [at] ingv [dot] it>
  • Jeremy D. Zechar <jeremy [dot] zechar [at] sed [dot] ethz [dot] ch>

Engaging Students and Teachers in Seismology: In Memory of John Lahr RSS

John Lahr was a curious, resourceful, hands-on seismologist who increased understanding of earthquakes, tectonics, and volcanic processes and who inspired teachers and students of all ages to listen to and explore the Earth. This session invites participants to present examples of effective programs, activities and techniques for actively engaging students and the public in seismology in the K-12 and college classroom, and in museums and other learning settings or opportunities. Descriptions of new technologies and ways to bring groups of teachers and students together are particularly encouraged.

Conveners

  • John Taber <taber [at] iris [dot] edu>
  • Larry Braile <braile [at] purdue [dot] edu>

The Evolution of Slow Slip and Tremor in Time and Space RSS

The temporal and spatial resolution with which we can measure slow slip and tremor in Cascadia have sharpened sufficiently that their evolution in time and space can be used as meaningful constraints on models of the underlying causative processes. This session will focus on observations of this evolution within Cascadia and comparisons with other regions, as well as on models that might explain these phenomena. Presentation topics may include the degree to which slow slip and/or tremor events are periodic, whether they propagate continuously or jump, how they start and stop, and at what scales various behaviors apply.

Conveners

  • Joan Gomberg <gomberg [at] usgs [dot] gov>
  • Evelyn Roeloffs <evelynr [at] usgs [dot] gov>

Ground Motion: Observations and Theory (Posters Only) RSS

        Convened by the Program Committee

 

The January/February 2010 Earthquakes in Haiti, Offshore Northern California, and Chile: Origins, Impacts and Lessons Learned RSS

On January 10 2010, a magnitude 6.5 earthquake ruptured a fault within the Gorda plate off the coast of Northern California, ending 15 years of relative seismic quiescence on California's North Coast and causing over $40 million in losses in Humboldt County. Three days later, a magnitude 7.0 earthquake occurred near Port-au-Prince, Haiti in an event that is likely to be listed as one of the great earthquake catastrophes of all time. We welcome papers addressing the mechanisms and tectonic settings of these earthquakes, the geotechnical factors, strong motion, remote sensing aspects, and direct observations of the earthquake zones including associated deformation, tsunami, landsliding and other evidence, as well as impacts and implications for regional seismic hazards. Addendum- This session will also include papers addressing these aspects of the Chile earthuake.

Conveners

  • Lori Dengler <Lori [dot] Dengler [at] humboldt [dot] edu>
  • Chris Goldfinger <gold [at] coas [dot] oregonstate [dot] edu>
  • Gavin Hayes <ghayes [at] usgs [dot] gov>
  • Chris Rollins <chrisrol [at] usc [dot] edu>
  •  

Joint Inversion of Multiple Geophysical Data Sets for Seismic Structure (Posters Only) RSS

A recent trend in the tomography arena at various scales is the joint inversion of traditionally distinct data sets for improved seismic structure modeling. Combinations of data sets used in these joint inversions have included: resistivity and magnetotelluric data; receiver function and surface wave dispersion observations; teleseismic or local travel times and gravity data; and surface wave velocity and gravity observations. Although multiple geophysical observations have been successfully inverted jointly, many questions about means and methods still remain unanswered.

We invite contributions to this session on simultaneous and/or sequential joint inversion methods for improved tomographic modeling. Of particular interest are studies that highlight novel combinations of data sets, possible relationships between the independent observations and the relative weighting of disparate data sets for successful inversion. Results from reservoir-scale to global-scale are welcome, along with new means to address computational efficiency and robustness of the inversion. To encourage more in-depth discussion, this will be a poster-only session.

Conveners

  • Monica Maceira <mmaceira [at] lanl [dot] gov>
  • Haijiang Zhang <hjzhang [at] mit [dot] edu>
  • Charlotte Rowe <char [at] lanl [dot] gov>

Magnitude Scaling and Regional Variation of Ground Motion (jointly sponsored by the European Seismological Commission) RSS

Abundant ground-motion data in both the large and small-to-moderate magnitude ranges are now available. These new data allow us to examine the magnitude (and distance) scaling of ground motions and its regional variability over a wide range of magnitudes. These data analysis results have important implications for the use of small and moderate earthquake data to determine or calibrate new ground-motion models and evaluate model applicability, and for the regionalization of global ground motion models in general.

We invite papers related to: 1) the analysis of ground-motion scaling and its regional variations; 2) the applicability of recent empirical models (e.g. Next Generation Attenuation (NGA) models) across regions and magnitude/distance ranges; 3) the adjustments of empirical models to specific site conditions or target-region characteristics; 4) the development of new strategies to select ground-motion models for Probabilistic Seismic Hazard Assessment studies; and 5) evaluation of ground motion model predictions against observed ground motions from recent earthquakes.

Conveners

  • Gail Atkinson <Gmatkinson [at] aol [dot] com>
  • Fabrice Cotton <fabrice [dot] cotton [at] obs [dot] ujf-grenoble [dot] fr>

Monitoring for Nuclear Explosions RSS

Seismology has new visibility with policymakers and the general public in the context of current evaluations of the Comprehensive Nuclear-Test-Ban Treaty. Explosion monitoring continues to motivate both innovation and funding in seismology, as it has since Project VELA began in 1959. Infrastructure to improve the monitoring of nuclear explosions has included the WWSSN (1960s to 1980s), the GSN (from 1990) and the International Monitoring System (from 2000). Many fundamental tools now used widely in seismology were developed partly to improve explosion monitoring, including seismic array signal processing, numerical simulation of seismic wave propagation, structure discovery methods such as tomography and receiver functions, and source characterization methods such as moment tensors and coda magnitude. We welcome papers related to all advances in monitoring capability in the last ten years. Such topics include discussion of new data streams and issues of accessibility; new understanding of source physics; assessments of capability; and improvements derived from new methods of analysis such as uses of three-dimensional models and massive data-mining. In addition to papers evaluating routine methods of event detection, association of signals, and event characterization, we welcome special studies of particular data sets, and discussion of monitoring technologies (such as ocean acoustics, infrasound, radiochemistry) that complement seismology.

Conveners

  • Paul G. Richards <richards [at] LDEO [dot] columbia [dot] edu>
  • Ola Dahlman <Ola [dot] Dahlman [at] ctbto [dot] org>
  • Bill Walter <bwalter [at] llnl [dot] gov>
  • Ray Willemann <ray [at] iris [dot] edu>

Near-Surface Deformation Associated with Active Faults RSS

This session will focus on imaging, characterizing, and modeling the near-surface expression of active faults using a broad array of geological and geophysical tools. Studies using new remote sensing methods that identify ground deformation (e.g., LiDAR, InSAR), imaging of subsurface deformation (e.g., seismic, radar), geologic mapping studies, and modeling of near-surface deformation above faults are encouraged for this session. Presentations describing methodologies and results from a broad array of tectonic and geologic settings are welcome.

Conveners

  • Lee M. Liberty <lliberty [at] boisestate [dot] edu>
  • Thomas L. Pratt <tpratt [at] ocean [dot] washington [dot] edu>

Numerical Prediction of Earthquake Ground Motion RSS

The last decade has witnessed significant improvements and developments in numerical methods for predicting earthquake ground motion in heterogeneous 3D media. By combining this methodological progress with increasing computational resources, it is becoming technically feasible to calculate realistic seismograms for frequencies of interest in seismic design applications.

The aim of this session is to give an up-to-date view of the capabilities to numerically predict earthquake ground motion, and to identify the challenges in fostering the use of numerical simulation in quantitative seismic hazard assessment.

We invite contributions focused on numerical modeling of earthquake ground motion, in particular on method development, verification and validation, and application to realistic cases. We strongly encourage contributions presenting large-scale simulations in heterogeneous media, possibly including spontaneous rupture, non- linear sediment response, and site-structure interaction.

Conveners

  • Emmanuel Chaljub <Emmanuel [dot] Chaljub [at] obs [dot] ujf-grenoble [dot] fr>
  • Steven M. Day <day [at] moho [dot] sdsu [dot] edu>
  • Peter Moczo <moczo [at] fmph [dot] uniba [dot] sk>

Operational Earthquake Forecasting RSS

Given the inability to forecast the occurrence of damaging shaking with high certainty and high probability, the application of earthquake forecasting to the evacuation of a large population has never seemed a realistic goal. Despite the large uncertainty over the imminence of a damaging earthquake, some more modest risk mitigation measures may be justified. Just as with other uncertain public threats, such as from pandemic disease or terrorism, prudent risk management may suggest useful societal actions, ranging from enhancing disaster preparedness and emergency response, to the reduction of threat exposure, to informing the public. By gauging the event probability gain associated with observational evidence, cost-benefit analysis can be applied to identify a spectrum of worthwhile mitigating actions. This operational earthquake forecasting bridges the gap between seismology and practical risk decision-making, and addresses the needs of civil authorities responsible for public safety. Just as with inter-disciplinary engineering seismology, this developing field promises to expand into a major branch of seismology.

Contributions to this session would cover time-dependent forecasting models able to run in real-time; review of past real events like the L'Aquila earthquake; comparison of the forecasting capabilities of different models (e.g. CSEP); real-time models for loss forecasting; and cost-benefit analysis for specific mitigation actions that may be taken in response to such forecasts.

Conveners

  • Michael Blanpied <mblanpied [at] usgs [dot] gov>
  • Gordon Woo <Gordon [dot] Woo [at] rms [dot] com>
  • Warner Marzocchi <warner [dot] marzocchi [at] ingv [dot] it>

Quantification and Treatment of Uncertainty and Correlations in Seismic Hazard and Risk Assessments RSS

Multi-location seismic hazard and risk assessments are not complete without proper treatment of uncertainty and correlation. All components of seismic hazard and risk studies, such as seismic source model, ground motion attenuation model, soil amplification model, and vulnerability model, contribute to the uncertainty. Each of these contributing models may have uncertainty in its functional form, as well as in the parameters used in the function. In general, two types of uncertainty can be identified, epistemic (modeling) and aleatory (inherent due to natural variability). Hazard and risk assessments are also affected by correlations in these various types of uncertainties (e.g., spatial correlation in ground motion intensity aleatory uncertainty, and in uncertain model coefficients). Spatial correlations are of particular interest when seismic hazard and risk are being estimated for a group of varying geographic locations. In this session, we will focus on quantification of these uncertainties at various levels (parameter, component, overall model), approaches for quantifying uncertainties, and guidance for uncertainty treatment in future studies.

Conveners

  • Tuna Onur <tuna [dot] onur [at] rms [dot] com>
  • Jack Baker <bakerjw [at] stanford [dot] edu>
  • Chris H. Cramer <ccramer [at] memphis [dot] edu>

Recent Advances in Source Parameters and Earthquake Magnitude Estimations RSS

Determination of the magnitude of an earthquake is one of the more important tasks of the seismological community. Indeed, accurate magnitude determinations are fundamental for studying the seismic source characteristics and are a primary source parameter input to many other applications (e.g., ShakeMap, earthquake catalogs for seismic hazard studies, etc.). The aim of the session is to gather researchers working in the earthquake source parameter observations and magnitude determination at local/regional and global scale. Contributions presenting results of testing and implementation of new IASPEI standards for the classical empirical magnitudes [such as ML, mb, mb(Lg), mB, MS(20) and MS(BB)] as well as modern physically based scales [such as Mw and Me], of innovative rapid magnitude procedures, of improved calibration functions, and of applications of these magnitudes to seismic hazard assessment and tsunami warning are encouraged.

Conveners

  • Domenico Di Giacomo <domenico [at] gfz-potsdam [dot] de>
  • George L. Choy <choy [at] usgs [dot] gov>

Seismic Hazard Mitigation Policy Development and Implementation RSS

Development and implementation of seismic hazard mitigation policy is complicated, involving seismologists and engineers, social scientists, economists, elected officials, and other stakeholders. In the United States, there is a pressing need for more robust and cost-effective seismic hazard mitigation policies at the national, state, and local level (i.e., county or municipality) to better address seismic risk. Implementation, at the local level is most critical in the United States, as it is most other countries. This special session provides a forum on how to bring seismologists, engineers, federal and state government officials, and private citizens together to develop and implement more effective policies for seismic hazard mitigation and risk reduction at national, state, and local levels. Case histories are especially welcome.

Conveners

  • Yumei Wang <yumei [dot] wang [at] dogami [dot] state [dot] or [dot] us>
  • Zhenming Wang <zmwang [at] uky [dot] edu>

Seismic Imaging: Recent Advancement and Future Directions RSS

Seismic imaging is a powerful tool for geophysicists to probe the Earth’s interior. The demand for higher resolution and a 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 include innovations and advances in 3D traveltime tomography, waveform tomography, receiver function mapping, and surface wave inversions. 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.

Conveners

  • Youshun Sun <youshun [at] mit [dot] edu>
  • Michael Begnaud <mbegnaud [at] lanl [dot] gov>

Seismic Networks, Analysis Tools, and Instrumentation (Posters Only) RSS

        Convened by the Program Committee

Seismic Structure and Geodynamics of the High Lava Plains and Greater Pacific Northwest RSS

The High Lava Plains (HLP) of Oregon has long represented an enigmatic region of massive tectonomagmatism in the Pacific Northwestern United States, with poorly understood relationships to the Columbia River Basalt sequence and the time-progressive tracks of both Newberry and Snake River Plain / Yellowstone rhyolitic volcanism. These events also tie directly to broader-scale mantle dynamics, including ongoing subduction of the Juan de Fuca plate system, extension across most of the Great Basin, and regional instability of lithosphere over a range of spatial scales. To provide new constraints on the structure and dynamics of these terranes, the area has been assaulted over the past 5 years by a host of high-density temporary broadband seismic networks, including EarthScope’s USArray Transportable Array, the High Lava Plains Broadband seismic experiment, and several USArray Flexible Array experiments. We encourage contributions to this session that not only address HLP-centered investigations, but also examine the structure and dynamics of the broader Pacific Northwestern United States and surrounding regions.

Conveners

  • Matthew J. Fouch <fouch [at] asu [dot] edu>
  • G. Randy Keller <grkeller [at] ou [dot] edu>
  • David E. James <james [at] dtm [dot] ciw [dot] edu>

 

Seismicity and Seismotectonics (Posters Only) RSS

Conveners

Jeanne Hardebeck <jhardebeck [at] usgs [dot] gov>

Diane Doser <doser [at] utep [dot] edu>

The Seismo-Acoustic Wavefield: Fusion of Seismic and Infrasound Data RSS

The field of seismo-acoustics is flourishing owing to the value of co-located seismic and infrasound arrays that sample both ground- and atmosphere-propagating elastic energy. The fusion of seismic and infrasonic data allows us to uniquely study a broad range of topics including the source physics of geophysical and man-made events, interaction of the atmosphere and lithosphere, source location and characterization, and inversion of atmospheric properties. Seismic sensors deployed near the solid earth atmosphere boundary can be affected by acoustic signals and thus the understanding of these interactions are important to seismic noise characterization. We invite abstracts on all aspects of seismo-acoustics, including general studies of infrasound from geophysical and anthropogenic sources that also generate seismic waves.

Conveners

  • Stephen Arrowsmith <arrows [at] lanl [dot] gov>
  • Jeff Johnson <jeff [dot] johnson [at] ees [dot] nmt [dot] edu>
  • Brian Stump <bstump [at] mail [dot] smu [dot] edu>

Seismology of the Atmosphere, Oceans, and Cryosphere RSS

Recently, there has been increased interest in Earth's seismic background wavefield and other nontraditional signals. Motivations include: (1) the ambient seismic wavefield can be used in tomographic imaging and seismic interferometry; (2) modern and historical records of microseism (5-25 s period) can be used as proxies for long-term ocean wave climate, which can in turn contribute to global climate studies; (3) increasing quantity, quality, distribution, and geographic coverage of seismic recording has resulted in the discovery of new glaciological, oceanic, and cryospheric signals and dynamic processes. This session welcomes studies that locate and characterize seismic noise/signal from a broad range of environmental and climate related sources. Topics can include characterizing the modal structure of microseismic energy, quantifying temporal variations in microseism properties, and interpreting seismic observations in the context of cryospheric, oceanographic and atmospheric source processes. We also welcome theoretical and numerical simulation studies of relevant seismic source and propagation models in all frequency bands.

Conveners

  • Daniel McNamara <mcnamara [at] usgs [dot] gov>
  • Keith Koper <koper [at] eas [dot] slu [dot] edu>
  • Richard Aster <aster [at] ees [dot] nmt [dot] edu>

State of Stress in Intraplate Regions RSS

Intraplate earthquakes pose an unexpected hazard for large continental areas. The paradigm for cyclic stress and fault rupture driven by high strain rates at plate boundaries does not seem to be appropriate within plate interiors where measured strain rates are relatively small. Yet, large intraplate earthquakes occur. Session submissions are encouraged that examine the conundrum of intraplate seismicity from observations of seismicity, geodesy, lithospheric rheology, potential fields, and relative and absolute stress measurements. We particularly encourage submissions that assess the progress made in crustal rheology through observational and laboratory experiments that place constraints on the state of stress in continental interiors.

Conveners

  • Christine Powell <capowell [at] memphis [dot] edu>
  • Charles Langston <clangstn [at] memphis [dot] edu>

Statistics of Earthquakes RSS

The purpose of this session is to solicit a wide range of papers concerned with the statistics and statistical physics of earthquakes. Subject matter includes but is not limited to frequency-size statistics, correlations in space-time-magnitude, patterns, forecasting, time series analyses, peaks-over-threshold analyses, record-breaking analyses, detrended fluctuation analyses, first passage time statistics, and similar phenomenology and analyses. Other topics might include reconstruction of paleoevents using statistical analyses, novel statistical methods of forecast validation and testing, and numerical simulations focusing on statistical exploration of simulation catalogs.

Conveners

  • Donald Turcotte <dlturcotte [at] ucdavis [dot] edu>
  • John Rundle <rundle [at] physics [dot] ucdavis [dot] edu>
  • James Holliday <jrholliday [at] ucdavis [dot] edu>
  • Mark Yoder <yoder [at] physics [dot] ucdavis [dot] edu>

Subsurface Imaging for Urban Seismic Hazards at the Engineering Scale RSS

Development of realistic seismic hazard maps for urban areas requires comprehensive investigation of faulting, basin geometry, rock properties, stratigraphy, and geotechnical properties. Damaging earthquakes frequently occur on unknown or poorly characterized faults below urban areas, have their energy trapped within poorly imaged sedimentary basins, with shaking further amplified at unexpected places by unknown basin and soil heterogeneity. This session focuses on current practice and future prospects for locating and characterizing faults and detailing basin boundaries and sediment properties with geophysical imaging techniques. Applying these methods to the seismic hazard of urban basins requires adapting techniques from the petroleum and mineral industries, and from crustal studies, to the noisy urban environment and the one-meter to one-kilometer engineering scale of most basins. We invite submission of examples showing how to attain detailed fault and basin characterization and imaging in urban areas with active and passive seismic, electromagnetic, and potential-field methods.

Conveners

  • John N. Louie <louie [at] seismo [dot] unr [dot] edu>
  • William J. Stephenson <wstephens [at] usgs [dot] gov>

Time Reversal in Geophysics RSS

The last decade has seen seismic source studies evolve from event-based observations to the permanent observation of large seismic networks. Recent seismic studies using new arrays and new methods of analysis have led to the recognition of heretofore unnoticed, complex fault motions (e.g., stick-slip to slow maybe diffuse rupture in deeper regions) as well as the recognition of the diversity of processes generating seismic energy (e.g., swarms, glacial earthquakes, background noise, volcanic tremor, non-volcanic tremor, etc.) Key ingredients to determine the processes underlying each observation are locating the origin point, probing source characteristics with a remotely recorded wavefield and producing high-resolution images.

Time Reversal (TR), only requiring synchronized recorded wavefields, is a promising approach for solution of the source location problem. The time reversal recipe, related to the adjoint formulation of the source problem and having empirical justification from laboratory experiments, is also closely related to seismic migration and interferometry. In comparison, TR focuses on source location and characterization.

Since its re-discovery in acoustics in the 1990s, various schemes have been developed for using time reversal in a range of applications, often very different from the source characterization problem. We seek to gather contributions related to time reversal in its diverse applications and disciplines (e.g., geophysics, material science) in order to offer the opportunity to expose and exchange ideas.

Conveners

  • Carene Larmat <carene [at] lanl [dot] gov>
  • Jean-Paul Montagner <jpm [at] ipgp [dot] jussieu [dot] fr>
  • Kees Wapenaar <C [dot] P [dot] A [dot] Wapenaar [at] tudelft [dot] nl>

Volcanic Plumbing Systems: Results, Interpretations and Implications for Monitoring RSS

A combination of improved instrumentation, improved network coverage and new techniques has led to an enhanced understanding of the plumbing systems beneath volcanoes, but the paths of magma accumulation and ascent are poorly known at most volcanoes. Because eruptions often begin exclusively with shallow seismicity, the geometry and characteristic behavior of the conduit system should be well known in order to best respond during a volcanic crisis. While many magmatic processes occur aseismically, the increased detection of broadband seismic signals at active volcanoes provides new insights into conduit geometries and processes. We invite papers that give results and interpretations of the plumbing systems beneath volcanoes including source mechanisms, tomography, and precise earthquake locations. We also encourage the presentation of methods and results that elucidate the time-dependent changes that occur within a plumbing system.

Conveners

  • Weston Thelen <wethelen [at] ess [dot] washington [dot] edu>
  • Gregory Waite <gpwaite [at] mtu [dot] edu>

 

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SSA 2010
April 20-23, 2010. Portland, OR.

Last Modified: 2010 Nov 12

Web: www.seismosoc.org