Earthquake Science Center Seminars
174 episodes - English - Latest episode: 13 days ago - ★★★★★ - 5 ratingsOpen dialogue about important issues in earthquake science presented by Center scientists, visitors, and invitees.
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Episodes
Unraveling Multi-Scale Fault Zone Behaviors with Small Earthquake Focal Mechanisms
April 10, 2024 17:30 - 1 hour - 261 MB VideoYifang Cheng, Tongji University, Shanghai Earthquake focal mechanisms offer insights into the architecture, kinematics, and stress at depth within fault zones, providing observations that complement surface geodetic measurements and seismicity statistics. We have improved the traditional focal mechanism calculation method, HASH, through the incorporation of machine learning algorithms and relative earthquake radiation measurements (REFOC). Our improved approach has been applied to over 1.5...
Offshore Fault Damage and Slip Behavior: Insights from Microseismicity and Seismic Imaging
April 03, 2024 17:30 - 1 hour - 216 MB VideoTravis Alongi, U.S. Geological Survey Many of the world’s most damaging faults are offshore, presenting unique challenges and opportunities for studying earthquakes and faults. This talk explores how earthquake-generated (passive) and human-made (active) marine seismic methods improve our knowledge of on-fault slip behavior and off-fault damage. The first part of my talk explores coupling along the poorly resolved shallow offshore portion of the southernmost Cascadia subduction zone...
Variable short-term slip rate on the Imperial fault modulated by filling of the Salton Trough by Lake Cahuilla
March 27, 2024 17:30 - 1 hour - 203 MB VideoThomas Rockwell, San Diego State University The Salton Basin was free of significant water between about 100 BCE and 950 CE but has filled to the sill elevation of +13 m six times between ca 950 and 1730 CE. Based on a dense array of cone penetrometer (CPT) soundings across a small sag pond, the Imperial fault is interpreted to have experienced an increase in earthquake rate and accelerated slip in the few hundred years after re-inundation, an observation that is also seen on the southern ...
Mechanics of caldera collapse earthquakes and their seismic representations
March 20, 2024 17:30 - 1 hour - 128 MB VideoTaiyi Wang, Stanford University All instrumented basaltic caldera collapses generate Mw > 5 very long period earthquakes. However, previous studies of source dynamics have been limited to lumped models treating the caldera block as rigid, leaving open questions related to how ruptures initiate and propagate around the ring fault, and the seismic expressions of those rupture dynamics. In the first part of my talk, I will present the first 3D numerical model capturing the nucleation and pr...
What does the 2024 M 7.5 Noto Hanto, Japan, quake tell us about short-term forecasting and long-term hazard?
March 13, 2024 22:00 - 1 hour - 213 MB VideoShinji Toda, Tohoku University The 1 Jan 2024 Noto Hanto earthquake launched a plethora of ills on the Noto Hanto population, taking 200 lives, and causing $25B in damage, only $5B of which was insured. These ills include a tsunami that arrived within a few minutes of the mainshock, as well as unexpectedly strong shaking throughout the Noto peninsula. In addition to direct shaking damage, the shaking triggered massive landslides in steep terrain, and caused extensive liquefaction in coast...
Tidally modulated icequake periodicity and its implication for rift zone dynamics
March 06, 2024 18:30 - 1 hour - 461 MB VideoMong-Han Huang, University of Maryland The Ross Ice Shelf (RIS) in Antarctica is the largest ice shelf in the world. As the RIS flows toward the Ross Sea, a buildup of tensile stress due to increasing ice flow velocity develops a series of flow-perpendicular rift zones. Although these rifts are essential in contributing to future calving and reduction in size of the ice shelf, their material properties and mechanical response to external stress in the rift zone scale (~10-100 km) are poorl...
Adventures in Measuring Variations in High-Frequency Radiation for Small to Moderate Earthquakes
February 28, 2024 18:30 - 1 hour - 136 MB VideoPeter Shearer, University of California, San Diego Similar-sized earthquakes vary in the strength of their high-frequency radiation and various modeling assumptions can be used to translate these differences into stress-drop estimates. Empirical methods are widely applied to correct earthquake spectra for path effects in order to estimate corner frequencies and stress drops, but suffer from tradeoffs among model parameters that hamper estimates of absolute stress drop and comparisons betwe...
A decade of prospective evaluations of earthquake forecasting models in California: What have we learned and what can we do with it?
February 21, 2024 18:30 - 1 hour - 131 MB VideoToño Bayona, University of Bristol The Collaboratory for the Study of Earthquake Predictability (CSEP) is a global community of scientists whose mission is to advance earthquake predictability research though the rigorous and prospective evaluation of probabilistic seismicity forecasts. One of CSEP’s major international achievements is the development and operation of dozens of time-varying and time-invariant seismicity models for California, including various versions of the well-es...
Spatial correlation in ground motion intensities: Measurement, prediction, and seismic risk implications
February 14, 2024 18:30 - 1 hour - 131 MB VideoJack W. Baker, Stanford University The amplitude of ground shaking during an earthquake varies spatially, due to location-to-location differences in source features, wave propagation, and site effects. These variations have important impacts on infrastructure systems and other distributed assets. This presentation will provide an overview of efforts to quantify spatial correlations in amplitudes, via observations from past earthquakes and numerical simulations. Regional risk analysis resul...
Probabilistic regional liquefaction hazard and risk analysis: A case study of residential buildings in Alameda, CA (In-person presentation)
January 24, 2024 18:30 - 1 hour - 386 MB VideoEmily Mongold, Stanford University The impact of liquefaction on a regional scale is not well understood or modeled with traditional approaches. This paper presents a method to quantitatively assess liquefaction hazard and risk on a regional scale, accounting for uncertainties in soil properties, groundwater conditions, ground shaking parameters, and empirical liquefaction potential index (LPI) equations. The regional analysis is applied to a case study to calculate regional occurrence rat...
The 17 January 1994 Northridge Earthquake: That was Then, This is Now
January 17, 2024 18:30 - 1 hour - 193 MB Video(1) Susan Hough, (2) Kate Hutton, (1) U.S. Geological Survey, (2) Caltech (retired) On the 30th anniversary of the 17 January 1994 Northridge, California, earthquake, we present a retrospective overview of an earthquake that had an enormous, multi-faceted impact in the greater Los Angeles area. In this two-part seminar, retired Caltech seismologist Kate Hutton first discusses the response to the earthquake by the (then) Southern California Seismic Network, which found itself slammed by jo...
Extremely Efficient Bayesian Inversions (or how to fit a model to data without the model or the data)
January 10, 2024 18:30 - 1 hour - 103 MB VideoSarah Minson, U.S. Geological Survey There are many underdetermined geophysical inverse problems. For example, when we try to infer earthquake fault slip, we find that there are many potential slip models that are consistent with our observations and our understanding of earthquake physics. One way to approach these problems is to use Bayesian analysis to infer the ensemble of all potential models that satisfy the observations and our prior knowledge. In Bayesian analysis, our prior kno...
(1) On-going research on EEW in Japan through STAR-E project, (2)Minimum information dependence modeling: a new approach to mixed-domain data analysis with higher-order interaction (in-person presentation)
December 08, 2023 21:30 - 1 hour - 295 MB Video(1) Stephen Wu, (2) Keisuke Yano, Institute of Statistical Mathematics, Japan (1) Since 2021, the Seismology TowArd Research innovation with data of Earthquake (STAR-E) project has been established by the Japanese government to promote interdisciplinary research between data science and seismology. Five proposals have been accepted to be the core projects of STAR-E and EEW has become a sub-project in one of the selected projects. In this talk, I will provide an overview of the plan to impr...
USGS/SCEC Community Stress Drop Validation Study (in-person presentation)
December 06, 2023 18:30 - 1 hour - 572 MB Video(1) Rachel Abercrombie, (2) Annemarie Baltay, (1) Boston University, (2) U.S. Geological Survey In 2021 we launched the Community Stress Drop Validation Study, focused on the 2019 Ridgecrest earthquake, California, sequence, using a common dataset. The broad aim of the collaboration is to improve the quality of estimates of stress drop and related fundamental earthquake source parameters (corner frequency, source duration, etc.) and their uncertainties, to enable more reliable ground motio...
Small-scale propagation of shallow creep events and environmental effects on the San Andreas fault, central California
November 29, 2023 18:30 - 1 hour - 544 MB VideoHeather Crume, California Geological Survey Surface creep has been documented on the San Andreas fault (SAF) since the 1960s. From Parkfield in the southeast to San Juan Bautista (SJB) in the northwest, the SAF is largely creeping and accommodating most of the ~38 mm/year right-lateral plate motion. The SJB section of the SAF lies at the northwest boundary of the central creeping section, forming a creeping-to-locked transition. These transition sections are known to be potential zones for...
Wedge Plasticity and a Minimalist Dynamic Rupture Model for the 2011 Mw 9.1 Tohoku-Oki Earthquake and Tsunami
November 15, 2023 18:30 - 1 hour - 135 MB VideoShuo Ma, San Diego State University One crucial yet unanswered question about the 2011 Tohoku-Oki earthquake and tsunami is what generated the largest tsunami (up to 40 m) along the Sanriku coast north of 39°N without large slip near the trench. A minimalist dynamic rupture model with wedge plasticity is presented to address this issue. The model incorporates the important variation of sediment thickness along the Japan Trench into the Japan Integrated Velocity Structure Model (JIVSM). By ...
Beyond Phase Picking: PhaseHunter’s Generalizable Approach to Seismic Signal Analysis Using Deep Learning Regression
November 08, 2023 18:30 - 1 hour - 94.4 MB VideoArtemii Novoselov, Stanford University This seminar introduces PhaseHunter, a deep learning framework initially designed for the precise estimation and uncertainty quantification of seismic phase onset times. Building upon this foundational capability, PhaseHunter has evolved to handle a broader range of seismic applications through a probabilistic deep learning regression approach. This enables the framework to analyze both continuous and binary properties of seismic signals, thereby exte...
The Generalized Long-Term Fault Memory Model and Applications to Paleoseismic Records
November 01, 2023 17:30 - 1 hour - 146 MB VideoJames Neely, University of Chicago Commonly used large earthquake recurrence models have two major limitations. First, they predict that the probability of a large earthquake stays constant or even decreases after it is “overdue” (past the observed average recurrence interval), so additional accumulated strain does not make an earthquake more likely. Second, they assume that the probability distribution of the time between earthquakes is the same over successive earthquake cycl...
Utilizing robotics and machine learning for fault zone mapping and fragile geological feature analysis (in-person presentation)
October 25, 2023 17:30 - 1 hour - 80.6 MB VideoZhiang Chen, California Institute of Technology The intricate and dynamic nature of fault zones and fragile geological features has long fascinated geoscientists and researchers. Understanding these geological phenomena is crucial not only for scientific exploration but also for hazard assessment and resource management. Recently, the convergence of robotics and machine learning has given rise to a transformative practice called automated geoscience. This practice utilizes robotics to auto...
Major southern San Andreas earthquakes modulated by lake-filling events (in-person presentation)
September 06, 2023 17:30 - 1 hour - 199 MB VideoRyley Hill, San Diego State University Both natural and anthropogenic hydrologic loads have been associated with stimulating seismicity. However, there are few documented examples that hydrologic loads can trigger large earthquakes. The southern San Andreas Fault (SSAF) in Southern California lies next to the Salton Sea, a successor of ancient Lake Cahuilla that periodically filled and desiccated over the past millennium. Here we use new geologic and paleoseismic data to demonstrate that t...
Earthquake forecasting in a data-rich era (in-person presentation)
August 30, 2023 17:30 - 1 hour - 93.4 MB VideoKelian Dascher-Cousineau, University of California, Berkeley Seismology is witnessing explosive growth in the diversity and scale of earthquake catalogs. A key motivation for this community effort is that more data should translate into better earthquake forecasts. In this presentation, I report on recent works in 1) improving aftershock forecasts, 2) investigating the seismic triggering potential of slow slip events, and 3) introducing deep learning methods for earthquake forecasting. Our...
What Controls the Earthquake Cycle?
August 23, 2023 17:30 - 1 hour - 212 MB VideoChristie Rowe, McGill University Earthquake recurrence in time and space is recorded in the rock record (deep/ long term) and sedimentary record (shallow/recent). Mechanistic understandings of earthquakes have not so far made a major contribution to forecasting but this could represent an area of scientific potential growth. In this talk I will review recent progress on understanding controls on the earthquake cycle from structural studies in the rock record. I will focus on evidence for...
Incorporating GNSS data into ShakeAlert (in-person presentation)
August 16, 2023 17:30 - 1 hour - 120 MB VideoJessica Murray, U.S. Geological Survey
Exploring Fault Evolution, Strength and Stresses in the Crust: Insights from Geodetic Imaging of Surface Rupturing Earthquakes
August 09, 2023 17:30 - 1 hour - 145 MB VideoChris Milliner, California Institute of Technology Understanding the mechanics of faulting and accurately assessing seismic hazards are crucial for mitigating the impact of earthquakes. This seminar investigates the use of satellite pixel tracking data to unravel fundamental geomechanical properties of fault systems by providing novel estimates of friction, the absolute magnitude of stresses in the Earth's crust and evolution of inelastic strain as fault systems mature. Here, I present a...
Are there geomagnetic precursors to earthquakes? - Two statistical studies from California (In-person presentation)
August 02, 2023 17:30 - 1 hour - 148 MB VideoKarl Kappler, QuakeFinder Short term (days to hours) earthquake forecasting is a hard scientific problem. Monitoring electromagnetic (EM) rather than mechanical/seismic activity may provide a breakthrough in this research. Anecdotal EM studies of single earthquakes lack of reproducible observations, and non-uniqueness of the anomalies when data are examined over the long term. However, in the early 2000s, a private humanitarian effort (QuakeFinder) was established to address the deficiency...
Understanding how lithospheric rheology modulates earthquake cycle dynamics and to what extent can rheological parameters be constrained by geodetic observations
July 26, 2023 17:30 - 1 hour - 510 MB VideoRishav Mallick, California Institute of Technology Viscoelastic processes in the upper mantle redistribute seismically generated stresses and modulate crustal deformation throughout the earthquake cycle. Geodetic observations of these motions at the surface of the crust-mantle system offer the possibility of constraining the rheology of the upper mantle. Parsimonious representations of viscoelastically modulated deformation through the aseismic phase of the earthquake cycle should simultan...
Harnessing Fiber Optic Distributed Acoustic Sensing for Earthquake Early Warning (Remote Presentation)
July 19, 2023 17:30 - 1 hour - 336 MB VideoItzhak Lior, The Hebrew University of Jerusalem Distributed Acoustic Sensing (DAS) is revolutionizing observational seismology by allowing for seismic measurement every few meters along tens-of-kilometers long optical fibers. One application bearing immense scientific and societal implications is the use of DAS for Earthquake Early Warning (EEW). For optimal warning times, seismic sensors should be installed as close as possible to expected earthquake sources. However, while the most hazar...
Induced Seismicity in the Raton Basin (In-Person Presentation)
July 12, 2023 17:30 - 1 hour - 128 MB VideoMargaret Glasgow, U.S. Geological Survey Fluid-injection induced seismicity has been ongoing for more than two decades in the Raton Basin, a coal-bed methane field located on the Colorado-New Mexico border. The uptick in seismicity began in 2001 approximately 10 years ahead of the central United States average. Sparse seismic instrumentation existed prior to 2015. Prior to denser instrumentation beginning in 2016, three broad zones of seismicity were identified. Each zone was suggested to ...
Near-fault velocity structure and ground motions of the 2019 M7.1 Ridgecrest earthquake
June 07, 2023 17:30 - 1 hour - 410 MB VideoTe Yang Yeh, San Diego State University We have simulated 0–3 Hz deterministic wave propagation in the Southern California Earthquake Center Community Velocity Model (CVM) version CVM‐S4.26‐M01 for the 2019 Mw 7.1 Ridgecrest earthquake. A data‐constrained high‐resolution fault zone model (Zhou et al., 2022) is incorporated into the CVM to investigate the effects of the near‐fault low‐velocity zone (LVZ) on the resulting ground motions, constrained by strong‐motion data recorded at ...
Variability in Earthquake Rupture Processes and Implications for Ground Motions: Insights from Recent Earthquakes in California and Nevada
May 17, 2023 17:30 - 1 hour - 531 MB VideoDaniel Trugman, University of Nevada, Reno The level of ground motion felt during an earthquake is controlled primarily by the size of the event and the distance from the source. However, it has long been understood that variations in rupture properties like stress drop and rupture directivity can cause earthquakes of equal size to generate significant differences in ground motion. This seminar will focus in detail on the relation between the rupture process and ground motions through case...
Next Generation Liquefaction Database and Model Development
April 26, 2023 17:30 - 1 hour - 465 MB VideoKenneth Hudson, UCLA Soil liquefaction and resulting ground failure due to earthquakes presents a significant hazard to distributed infrastructure systems and structures around the world. Currently there is no consensus in liquefaction susceptibility or triggering models. The disagreements between models is a result of incomplete datasets and parameter spaces for model development. The Next Generation Liquefaction (NGL) Project was created to provide a database for advancing liquefaction r...
Loma Prieta again—Subsurface Geology and the San Andreas Fault in the Southern Coast Range
April 12, 2023 17:30 - 1 hour - 189 MB VideoGary Fuis, USGS The 1989 M 6.9 Loma Prieta earthquake is the first major event to occur along the San Andreas fault (SAF) zone in central California since the 1906 M 7.9 San Francisco earthquake. Given the complexity of this event, uncertainty has persisted as to whether this earthquake ruptured the SAF itself or a secondary fault. Recent work on the SAF in the Coachella Valley, in southern California, has revealed similar complexity, arising from a non-planar, non-vertical fault geometry,...
February 6, 2023 earthquakes in Türkiye
April 05, 2023 17:30 - 1 hour - 234 MB VideoMustafa Erdik, Bogazici University On Feb. 6, 2023, a magnitude Mw7.8 earthquake struck near Pazarcık City in south-central Türkiye, followed by a magnitude Mw 7.5 event about 9 hours later. The presentation will cover the explanation of what happened, including the fault rupture, strong ground motion, building codes, and damages. The reasons behind extensive damages, associated casualties, and the ways of reducing them will also be discussed.
February 6, 2023 Kahramanmaraş Earthquakes: An Initial Assessment of Recorded Ground Motions and Observed Damages
March 29, 2023 17:30 - 1 hour - 448 MB VideoAyşegül Askan, Middle East Technical University On Feburary 6, 2023, two earthquakes with M7.8 and M7.5 occurred in Southeastern Türkiye only hours apart and caused significant damage and fatalities. The effects of these events were very widespread with complex source and site effects as well as major geotechnical and structural damages. The mainshocks and their aftershock sequences were recorded in a large region by the national strong motion network of Türkiye, operated by AFAD. This pre...
A Retrospective Look at the 1933 Long Beach Earthquake: Historical Context, Impact, and Modern Science
March 22, 2023 17:30 - 1 hour - 175 MB VideoSusan Hough, USGS At estimated magnitude 6.4, the Long Beach earthquake was only moderately large. Whereas the 1906 San Francisco earthquake had a profound impact on earthquake science, leading to the development of elastic rebound theory, the Long Beach earthquake arguably had a larger impact on earthquake risk reduction. The earthquake occurred at a pivotal time, after the start of earthquake monitoring in southern California, but at a time when the severity of earthquake hazard in sou...
Liquefaction or liquefiction? Anthropogenic regulation and the influence of evaporite dissolution on ground failure in the 2019 Mw 7.1 Ridgecrest Earthquake and beyond
March 15, 2023 17:30 - 1 hour - 240 MB VideoPaula Burgi Remote sensing observations of the 2019 Ridgecrest, California, earthquake sequence revealed a significant amount of surface ejecta in the nearby Searles Lake, including one area where the surface ejecta was arranged in a repeating hexagonal “honeycomb” pattern. This pattern is collocated with injection wells from a solution mining operation, suggesting anthropogenic activities influenced the spatial distribution of surface ejecta. Lithology, geotechnical soil behav...
Scalable Monitoring of Infrastructure through Non-dedicated Sensors
March 01, 2023 18:30 - 1 hour - 190 MB VideoHaeyong Noh, Stanford With increasing urbanization, civil infrastructure plays key roles in connecting, protecting, and supporting this growing population in cities. However, the large stock of aging infrastructure poses significant challenges to the economy and public safety. Smart structures are designed to sense, understand, and respond to the structural state and the human needs, but traditional monitoring approaches using dedicated sensors often result in dense sensing systems that ar...
The November 3, 2002 Mw 7.9 Denali Fault Earthquake, Alaska: It’s Geological, Seismological, and Engineering Legacy
February 27, 2023 18:30 - 1 hour - 214 MB VideoDavid Schwartz, Scientist Emeritus, USGS The Mw 7.9 Denali fault, Alaska earthquake of Nov. 3, 2002 was one of only nine earthquakes in shallow continental crust, worldwide, larger than magnitude 7.8 since 1900. The complex faulting, which involved the Susitna Glacier thrust fault, the principal Denali strike-slip fault, and the Totschunda branch of the Denali fault occurred along 351 km of the 1200 km-long Denali fault system. Right-lateral surface offsets of 4.5–5.1 m, with a maxim...
¡Alerta! Engineering on Shaky Ground
February 15, 2023 18:30 - 1 hour - 122 MB VideoElizabeth Reddy, Colorado School of Mines The Sistema de Alerta Sísmica Mexicano is the world's oldest public earthquake early warning system. This talk by the author of the new book, ¡Alerta! (forthcoming in 2023 MIT Press), draws on over a decade of ethnographic and archival research to analyze how SASMEX and related Mexican efforts have sought to change relationships between the environment, society, and technology and develop insights relevant for risk mitigation projects more broadl...
Megathrust seismicity holes and coronas: What they mean for hazard, and the hunt for prehistoric subduction events
February 08, 2023 18:30 - 1 hour - 133 MB VideoRoss Stein, Temblor
Absolute stress levels on mature faults: Bridging insight from the lab and field using physics-based modeling
January 25, 2023 18:30 - 1 hour - 151 MB VideoValere Lambert Determining principles and conditions governing motion along faults is crucial for assessing how earthquake ruptures start and how large they may ultimately become. One of the most notable constraints for the stress levels along mature plate boundary faults is the abundance of evidence that the resistance to shear motion during substantial fault slip must be low (< 20 MPa). Two end-member hypotheses are used to explain such low-stress operation of mature faults: either (I) m...
Kinematic slip models of four large Intermountain West earthquakes of 2020 and 2021
January 18, 2023 18:30 - 1 hour - 238 MB VideoFred Pollitz, USGS Four large earthquakes struck the Intermountain West and Basin and Range Province in 2020 and 2021: M5.7 March 18, 2020 Magna, Utah; M6.5 March 31, 2020, Stanley, Idaho; M6.5 May 15, 2020 Monte Cristo Range, Nevada; and M6.0 July 8, 2021 Antelope Valley, California, earthquake. As noted by Wesnousky (2020 SRL), each of the first three occurred in areas of relatively high background seismicity and geodetic strain rate; the same is true for the Antelope Valley earthquake. ...
How Large Is the Spatial Area Influencing Site Response: Insights Gained from Multidimensional Analyses at the Treasure Island Downhole Array
January 04, 2023 18:30 - 1 hour - 213 MB VideoMohamad Hallal, UC Berkeley When attempting to model seismic site effects, most studies have focused on the importance of vertically characterizing subsurface geomaterials. However, laterally characterizing the geomaterials’ variability has generally been either overlooked or oversimplified. As such, little is actually known about the spatial area that influences seismic site response. This presentation will share insights that have been gained regarding the spatial area that influen...
Roles of Dynamic Rupture Simulations in the Development of Next Generation Probabilistic Fault Displacement Hazard Analysis (PFDHA) Models
November 30, 2022 18:30 - 1 hour - 249 MB VideoYongfei Wang, SCEC Coseismic fault displacements in large earthquakes have caused significant damage to structures and lifelines located on or near fault lines. For buildings or distributed infrastructure systems located near active faults, engineering displacement demands are defined using probabilistic fault-displacement hazard analysis (PFDHA) models. However, fault displacement models (FDMs) used in PFDHA are sparse and poorly constrained in part due to the scarcity of direct observati...
Subregional anelastic path effects in California
November 16, 2022 18:30 - 1 hour - 200 MB VideoTristan Buckreis, UCLA Next Generation Attenuation (NGA) West2 ground motion models (GMMs) include regional path adjustments for broad geopolitical regions. We extend that framework to account for systematic variations in anelastic attenuation for nine physiographical subregions in California that are defined in consideration of geological conditions. Using a large database that is approximately doubled in size for California relative to NGA-West2, we find relatively fast attenuation in co...
Seismoelectric effects for subsurface characterization
November 09, 2022 18:30 - 1 hour - 209 MB VideoChristina Morency, Lawrence Livermore National Laboratory Classical approaches for Earth subsurface imaging rely predominantly on seismic techniques, which alone do not directly capture fluid-specific properties. On the other hand, electromagnetic (EM) measurements add constraints on the fluid phase through, for example, electrical conductivity. However, EM signals alone do not offer direct information of solid properties. In the recent years, there have been efforts to combine seismic and...
Accessible and Multi-Lingual Earthquake Safety Messaging
October 26, 2022 17:30 - 1 hour - 212 MB VideoMark Benthien, Earthquake Country Alliance The Earthquake Country Alliance has created a variety of earthquake safety messaging documents in the top 16 languages spoken and read in California, at www.EarthquakeCountry.org/languages. Each document is also accessible for people who use screen reader technology. Funding for the ongoing project is provided to the California Governor’s Office of Emergency Services by FEMA (NEHRP) and subgranted to the Southern California Earthquake Center...
WaveDecompNet: a multi-task encoder-decoder network to separate earthquake and ambient noise signals in seismograms
October 19, 2022 17:30 - 1 hour - 184 MB VideoJiuxun Yin, Caltech Seismological Laboratory Seismograms contain multiple sources of seismic waves, from distinct transient signals such as earthquakes to continuous ambient seismic vibrations such as microseism. Ambient vibrations contaminate the earthquake signals, while the earthquake signals pollute the ambient noise's statistical properties necessary for ambient-noise seismology analysis. Separating ambient noise from earthquake signals would thus benefit multiple seismological analys...
Advancing the Frontier of Subduction Zone (Earthquake) Science, by the USGS and its Partners
October 12, 2022 17:30 - 1 hour - 252 MB VideoJoan Gomberg, USGS Like many of its partners, the USGS has recognized the tremendous opportunity for advancing earthquake science that subduction zones (SZs) offer, because of 1) the extraordinary diversity of SZ earthquakes and other natural phenomena they initiate and respond to, 2) the new perspectives inspired by required multi-disciplinary and international work, and 3) technological advances enabling offshore exploration. Participation of USGS personnel in SZ-relevant partners’...
Fracture behavior at low effective stress
September 28, 2022 17:30 - 1 hour - 68.6 MB VideoHarry Lisabeth, Lawrence Berkeley National Laboratory The behavior of the upper crust is controlled in large part by fractures. Fractures are the conduits of fluid flow, facilitate reactions and transport of mass, and mediate deformation large and small. Fractures are not static features, but rather are sensitive to the hydraulic, chemical and mechanical environment in which they are set. I'll present the results of a multimodal experimental study of the physical properties of fluid-sat...