Yifang 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...

Travis 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...

Thomas 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...

Taiyi 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...

Shinji 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...

Mong-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)...

Peter 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...

Toño 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...

Jack 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...

Emily 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...

(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...

Sarah 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...

(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...

(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...

Heather 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...

Shuo 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...

Artemii 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,...

James 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...

Zhiang 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...

Ryley 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...

Kelian 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...

Christie 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...

Jessica Murray, U.S. Geological Survey