Meeting Abstracts

SCEC Annual Meeting participants are invited to share recent results and activities relevant to SCEC priorities and initiatives during the poster sessions. The SCEC collaboration emphasizes the connections between information gathering by sensor networks, fieldwork, and laboratory experiments; knowledge formulation through physics-based, system-level modeling; improved understanding of seismic hazard; and actions to reduce earthquake risk and promote resilience.

Use the search form to view abstracts of presentations that have been accepted for this meeting.

Results 201-248 of 248

SCEC ID	Category	Title and Authors	SCEC Award
Poster 010	Geology	New Perspectives on Newport-Inglewood Fault Geometry Natasha Toghramadjian, Andreas Plesch, Izabella Sabharwal, John Shaw The Newport-Inglewood Fault is an active, right-lateral fault system that forms the southwestern edge of the Los Angeles Basin and passes through one of the most intensely urbanized regions of California. The southern portion of the fault ruptured... more
Poster 017	Geology	Airborne Thermal-Infrared Spectral Survey of the 2019 Ridgecrest Earthquake Zone and Environs David Tratt, Eric Keim, Kerry Buckland, Patrick Johnson, Ira Leifer A quick-reaction investigation was undertaken of the area affected by the swarm of major and minor earthquakes that struck the Ridgecrest, CA locale in July 2019. Using surface rupture coordinates derived from USGS field observations, airborne... more
Talk	Seismology	Imaging Stress and Faulting Complexity Through Earthquake Waveform Similarity Daniel Trugman, Zachary Ross, Paul Johnson While the rupture processes of nearby earthquakes are often highly similar, characterizing the differences can give insight into the details of the local stress field and in-situ fault network. In this work, we perform a comprehensive analysis of... more
Poster 067	Seismology	Spatio-temporal variations of low-frequency aftershocks of the 2019 Ridgecrest earthquake sequence Ayako Tsuchiyama, Taka'aki Taira, Junichi Nakajima, Roland Bürgmann Low-frequency earthquakes (LFEs) generally have relatively stronger spectral components in the lower frequency range, compared to what is expected based on their magnitude. This type of earthquake has been considered to be generated in some... more
Poster 183	CXM	Integrated fault mesh of Southern California in finite element models of structural geometric complexities, crustal heterogeneity, and topography Sui Tung, Manoochehr Shirzaei, Timothy Masterlark Southern California (SC) inherits one of the highest fault density among other seismogenic regions around the globe. The vast efforts of the SCEC Community Models (CXMs) have been developing numerous datasets and models that describe the SC tectonic... more
Talk	Geodesy	InSAR observations of accelerated shallow creep on California faults Ekaterina Tymofyeyeva Advances in InSAR data acquisition allow the modern satellite missions to make surface displacement measurements at high spatial resolution and frequent repeat times in areas where data from other geodetic instruments may be sparse or unavailable.... more
Poster 181	CXM	Current status and future plans for the Community Geodetic Model (InSAR) products Ekaterina Tymofyeyeva, David Sandwell, Xiaohua Xu, Zhen Liu, Kathryn Materna, Kang Wang, Gareth Funning, David Bekaert, Michael Floyd The goals of the Community Geodetic Model (CGM; https://www.scec.org/research/cgm) areis to create a consensus model of the crustal motions in Southern California at high spatial and temporal resolutions and to provide a product that is easily... more	20074, 20092, 20071
Poster 081	Seismology	Spatial variations in seismicity characteristics in and around the source region of the 2019 Yamagata-Oki Earthquake, Japan Taku Ueda, Aitaro Kato, Yosihiko Ogata, Lina Yamaya The 2019 Mj 6.7 Yamagata-Oki Earthquake occurred off the coast of Yamagata Prefecture, Japan, on 18 June 2019. This earthquake occurred adjacent to the northeastern edge of the source region of the 1964 Niigata Earthquake. Few aftershocks occurred... more
Poster 162	FARM	Surface Displacement and Ground Motion from Dynamic Rupture Models of Thrust Faults with Variable Dip Angles and Burial Depths Sirena Ulloa, Julian Lozos Thrust-fault earthquakes are particularly hazardous in that they produce stronger ground motion than normal or strike-slip events of the same magnitude due to a combination of hanging-wall effects, vertical asymmetry, and higher stress drop due to... more	18218
Poster 150	FARM	Scale-dependent fault roughness effects on earthquake dynamics and ground-motion Thomas Ulrich, Alice-Agnes Gabriel The effects of fault roughness on earthquake rupture dynamics and the radiated seismic wave field have received increasing attention in numerical models aiming to capture the full frequency range of observed ground motions. We here investigate scale... more	20046
Poster 026	SAFS	Creep rate gradient through the locked-to-creeping transition zone measured by differential lidar on the San Andreas fault at Parkfield, CA Michael Vadman, Sean Bemis The San Andreas fault (SAf) near Parkfield, CA, transitions from fully locked to creeping over 50 km of fault length, approaching a surface creep rate of ~25 mm/yr. The gradient in surface creep rate is illustrated through measurements at several... more	19126
Poster 088	EFP	Measuring robust b-values from magnitude differences Nicholas van der Elst The earthquake magnitude-frequency distribution is characterized by the b-value, which describes the relative frequency of large vs. small earthquakes. There is evidence to suggest that the b-value for aftershocks is larger than for background... more
Poster 093	EFP	Assimilating Multicycle Rupture Simulations into Probabilistic Forecasting Models Luis Vazquez, Thomas Jordan A general problem in earthquake forecasting is how to assimilate deterministic physical simulations into probabilistic forecasting models. Here we focus on combining long earthquake catalogs (~ 10 6 yr) from the multi-cycle Rate-State Quake... more
Poster 143	FARM	Weak phases production and heat generation control fault friction during seismic slip Manolis Veveakis, Hadrien Rattez The triggering and magnitude of earthquakes is determined by the friction evolution along faults. Experimental results have revealed a drastic decrease of the friction coefficient for velocities close to the maximum seismic one, independently of the... more	19026
Poster 042	Seismology	Using Seismic and Gravity Measurements to Map the 3D Structure of the San Gabriel and San Bernardino Basins Valeria Villa, Robert Clayton, Patricia Persaud Sedimentary basins like the San Gabriel and San Bernardino basins in Southern California are thought to trap and amplify seismic waves because of the impedance contrast between rock layers and concave shape. With the low-velocity sediments... more
Poster 235	CEO	San Bernardino County Emergency Response to July 4th-5th Trona-Ridgecrest Earthquake Complex Miles Wagner, Frank Jordan After the July 4th-5th Trona-Ridgecrest Earthquake Complex shook the Trona area, San Bernardino County responded by providing emergency aid and starting the recovery process. Pre-planned activities and information gathering started, including... more
Poster 039	Seismology	Layered Structure and Vs30 at Colocated Pressure and Seismic Stations in the Transportable Array Jiong Wang, Toshiro Tanimoto In this study, we present layered structure and Vs30 at many Transportable Array (TA) stations by performing an inversion approach with low-frequency seismic noise generated by surface pressure changes. The main source of seismic noise below 0.05 Hz... more	19039, 20072
Poster 115	SDOT	Modeling of postseismic deformation following the 2019 Ridgecrest earthquake sequence Kang Wang, Roland Bürgmann The 2019 Ridgecrest earthquake sequence culminated in the largest seismic event in California since the 1999 Mw 7.1 Hector Mine earthquake. Here we use Sentinel-1 and Cosmo-SkyMed (CSK) InSAR, as well as GNSS data to study the postseismic... more	20016
Poster 220	GM	A frequency-dependent spatial correlation model of within-event residuals for Fourier amplitude spectra Nan Wang, Kim Olsen, Steven Day We have developed an empirical spatial correlation model of normalized within-event residuals for the Fourier Amplitude Spectra (FAS), as FAS is a more straightforward representation of the ground motion frequency content than the traditionally-used... more
Poster 069	Seismology	Study of fault zone damage and healing in the 2019 Ridgecrest aftershock sequence Wei Wang, John Vidale The structure and evolution of faults is a key to understanding earthquake fault systems and the earthquake cycle. By velocity weakening and strain localization, faults generate earthquakes from plate motions. One outstanding question is just how... more
Poster 068	Seismology	Isotropic source components of events in the 2019 Ridgecrest earthquake sequence Xin Wang, Yifang Cheng, Zhongwen Zhan, Yehuda Ben-Zion We investigate source mechanisms of 256 M3.5+ aftershocks of the 2019 M7.1 Ridgecrest earthquake, which ruptured a complex fault system in the Eastern California Shear Zone. The full moment tensors are derived with a generalized “Cut and Paste”... more	20021
Poster 154	FARM	Validate simulated fault displacements from dynamic rupture against the observed in the 1992 Landers earthquake Yongfei Wang, Christine Goulet Coseismic fault displacements in large earthquakes have caused significant damage to structures and lifelines located on or near fault lines. Examples include severely damaged bridges, dams and tunnels in the 1999 Chi-Chi earthquake, pancaked... more
Poster 117	SDOT	Vertical Deformation Dependency on Spatially Variable Elastic Plate Thickness: Insights from the 2019 Ridgecrest Earthquake Sequence Lauren Ward, Bridget Smith-Konter, Xiaohua Xu, David Sandwell Benefiting from both spatially and temporally dense instrumentation and remotely sensed observations, deformation from the 2019 Ridgecrest earthquake sequence is poised to become one of the best observed co- and postseismic processes to date. These... more	19161
Talk	EFP	Experimental Design for Testing Hypotheses of Earthquake Precursors Maximilian Werner Generations of earthquake scientists have proposed the existence of observable precursory earthquake activity, but few have offered a scientific plan for testing their ideas. Recently proposed hypotheses include precursory aseismic slip driving... more	20076, 19235
Poster 062	Seismology	Detailed traveltime tomography and seismicity around the 2019 M7.1 Ridgecrest, CA, earthquake using dense rapid-response seismic data Malcolm White, Hongjian Fang, Rufus Catchings, Mark Goldman, Jamison Steidl, Yehuda Ben-Zion We derive detailed 3D models of seismic P- and S-wave speeds (Vp and Vs, respectively) and a local earthquake catalog for the region around the 2019 Mw7.1 Ridgecrest earthquake in the Eastern California Shear Zone. The study uses traveltimes from... more
Poster 023	SAFS	Investigating the Earthquake Chronology of the Last Millennium along the Cholame Section of the San Andreas Fault Alana Williams, Ramon Arrowsmith, Thomas Rockwell The Cholame section of the SAF is located between the Parkfield section and the locked Carrizo section. This portion of the fault is significant because it marks a behavioral transition between Parkfield in the north with its creep and numerous M6... more
Poster 233	EEII	Structural healing of Millikan Library over 20 years of continuous seismic monitoring Ethan Williams, Thomas Heaton, Valere Lambert, Zhongwen Zhan Since 2001, the Southern California Seismic Network has archived continuous waveform data from strong motion station CI.MIK in Caltech’s Robert A. Millikan Memorial Library, a nine-story reinforced concrete building. A simple spectral analysis of... more
Poster 029	SAFS	HOW FAULT ROCKS FORM AND MATURE IN THE SHALLOW SAN ANDREAS FAULT Randolph Williams, Christie Rowe, Kristina Okamoto, Heather Savage, Erin Eves We document the mechanical and geochemical pathways of fault-rock development in the shallow San Andreas fault, and quantify their importance in shaping the mineralogy, grain size, fabric, and frictional characteristics of gouge. Using a combination... more	19166, 18189
Poster 198	GM	Generation of Broadband Ground Motion from Dynamic Rupture Simulations: A Group Modeling Approach towards better Characterizing Seismic Hazard for Engineering Applications Kyle Withers, Shuo Ma, Yongfei Wang, Alice-Agnes Gabriel, Luis Dalguer, Thomas Ulrich, Christine Goulet In areas of infrequent seismicity or where geologic structures (e.g., sedimentary basins) complicate seismic wave propagation, earthquake ground-motion simulations provide one approach to improving the accuracy of ground-motion predictions for... more	20046
Poster 161	FARM	How do inertia, free surface interaction, and absolute friction coefficient level affect the final slip amplitude in a theoretical thrust fault rupture model? Baoning Wu, David Oglesby, Christodoulos Kyriakopoulos, Kenny Ryan Estimating the fault slip distribution for a future large earthquake is a key problem in earthquake physics with important implications for mitigating earthquake hazards. In principle, one can estimate the fault slip with a mechanical model: when... more
Poster 077	Seismology	COVID-19 Societal Response Captured by Seismic Noise in China and Italy Han Xiao, Zachary Eilon, Chen Ji, Toshiro Tanimoto Seismic noise with frequencies above 1 Hz is often called “cultural noise” and is generally correlated quite well with human activities. Recently, cities in mainland China and Italy imposed restrictions on travel and day-to-day activity in response... more
Poster 072	Seismology	Rupture process of the 2019 M 6.4 and M 7.1 Ridgecrest earthquakes imaged with local and teleseismic back-projections Yuqing Xie, Lingsen Meng, Han Bao We used the multi-array local back-projections (MLBP) and slowness-enhanced back-projection (SEBP) to image the coseismic rupture process of the 2019 M 6.4 and M 7.1 Ridgecrest, California earthquake sequence, which occurs on multiple complex fault... more
Poster 104	Geodesy	Surface deformation nearby the Ridgecrest earthquakes: Frictional slip or compliant fault? Xiaohua Xu, David Sandwell, Lauren Ward, Bridget Smith-Konter, Chris Milliner, Peng Fang, Yehuda Bock High resolution Interferometric Synthetic Aperture Radar observations reveal a large number of linear strain concentrations (or fractures) surrounding the 2019 Ridgecrest earthquake sequence; more than 80% had not been mapped previously. In this... more	19083
Poster 210	GM	The Potential of DAS in Seismic Hazard Analysis: A Case Study of Ridgecrest City DAS Array Yan Yang, Ethan Williams, Jack Muir, Zhongwen Zhan Shallow shear-velocity structure is closely related to earthquake ground motion intensity. However, the shallow structure often has vertical and lateral heterogeneities over very small distances that can only be resolved by high-resolution, high-... more
Poster 207	GM	3D wave propagation simulations of the 2019 M7.1 Ridgecrest, CA, Earthquake Te-Yang Yeh, Kim Olsen We performed 3D numerical wave propagation simulations for the July 6 2019 M7.1 Ridgecrest, CA earthquake in a 200 km by 300 km model domain. The purpose of this study is to use a state-of-the-art 3D simulation tool to reproduce the broadband ground... more	20157
Poster 019	Geology	Testing the Reproducibility of Remote Surface Rupture Maps of the 2019 Ridgecrest Earthquakes Elaine Young, Michael Oskin, Alba Rodriguez Padilla We present an independent effort to use post-earthquake lidar data and other imagery to remotely map surface ruptures and measure offsets produced by the 2019 Ridgecrest Earthquake sequence. The 4 July MW 6.4 and 5 July MW 7.1 earthquakes produced... more	20155
Poster 192	CS	Cloud Computing and Big Data – Using the Southern California Earthquake Data Center (SCEDC) and the Southern California Seismic Network (SCSN) Products and Services for Earthquake Research Ellen Yu, Prabha Acharya, Aparna Bhaskaran, Shang-Lin Chen, Jennifer Andrews, Valerie Thomas, Zachary Ross, Egill Hauksson, Robert Clayton Southern California Earthquake Data Now in the Amazon Cloud (s3://scedc-pds us-west-2 region.) - We have uploaded the following parts of the SCEDC archive into the AWS public dataset: - Continuous waveforms:100 sps, 40 sps, 20 sps and 1 sps... more	20051
Talk	EFP	Localization and coalescence of seismicity before large earthquakes in California Ilya Zaliapin This talk discusses an ongoing project focused on localization of deformation around faults that are generally locked in the interseismic periods before the occurrence of large earthquakes. It has been long known from laboratory fracture experiments... more	20065
Talk	Seismology	A rapid response Distributed Acoustic Sensing (DAS) array after the 2019 Ridgecrest earthquakes Zhongwen Zhan, Zefeng Li, Zhichao Shen, Yan Yang, Ethan Williams, Xin Wang, Jack Muir, Andrew Klesh, Martin Karrenbach Distributed Acoustic Sensing (DAS) is a new technology that can convert kilometers of pre-existing fiber optic cable into a dense seismic array. DAS has demonstrated strong potential in both seismicity monitoring and subsurface imaging. Within a few... more
Poster 103	EFP	Study on the background and triggering seismicity in Yutian, Xinjiang, China region Shengfeng Zhang, Yongxian Zhang, Jiancang Zhuang, Zhongliang Wu Several earthquakes of magnitude 6.0 or above have occurred in Yutian, Xinjiang, China, and a MS6.4 earthquake occurred in this area again on June 26, 2020 in Beijing time. After the earthquake, the Institute of Earthquake Forecasting, China... more
Poster 055	Seismology	Building a new catalog for induced earthquakes in Oklahoma based on a 3-D velocity model Shuo Zhang, Bingxu Luo, Hejun Zhu Over the past decade, seismologists observed a significant increase in the seismicity rate in Oklahoma, which reached to a maximum level in 2016, then gradually decreased to a normal level recently. Unlike inter-plate earthquakes, these intra-plate... more
Poster 054	Seismology	Environmental triggering of seismicity in California Bruce Zhou, Ilya Zaliapin, Christopher Johnson, Yuning Fu, Kristel Chanard, Yehuda Ben-Zion Exploring the potential triggering of earthquakes by environmental forcing terms, such as water mass loading and surface temperature changes, contributes to the understanding of crustal mechanics and dynamics of seismicity. The various geological... more	20065
Poster 082	Seismology	Weak Off-fault Structures Revealed by Microseismicity along Xiaojiang Fault Zone (China) and Their Implications for Seismic Hazard Assessment Yijian ZHOU, Shiyong ZHOU, PKU Yue, Li Zhao, Zhousheng YANG, Yuan YAO The Xiaojiang Fault Zone (XJF) is located in the southeastern margin of the Tibetan Plateau, which defines the boundary between the South China and Sichuan-Yunnan blocks. Seismic hazard assessment of XJF is of great scientific and societal... more
Poster 064	Seismology	Machine Learning-Based Tomography of the Ridgecrest Region Zheng Zhou, Peter Gerstoft, Michael Bianco, Kim Olsen We perform ambient noise tomography using data recorded from Nodal arrays within a ~50 km by 50 km area including the July 2019 M7.1 and M6.4 Ridgecrest, CA, earthquakes. Our preliminary imaging using a conventional least squares approach reveals a... more
Poster 146	FARM	Ascending fluids and overpressure pulses on faults drive aseismic slip and swarm seismicity Weiqiang Zhu, Yuyun Yang, Kali Allison, Eric Dunham It is well established that fault damage zones are conduits for fluids, and that changes in pore fluid pressure and flow alter fault strength. Despite this, most earthquake models prescribe pore pressure and neglect the evolution of pressure and... more	19074
Talk	FARM	Probing fault nucleation and propagation using dynamic microtomography experiments Wen-lu Zhu, Francois Renard From the stick slip instability to the rate-and-state frictional law, experimental rock deformation has enabled much of our current understanding of earthquake physics. However, quantitative earthquake assessment using laboratory-derived... more
Poster 101	EFP	An ETAS model incorporated with focal mechanisms Jiancang Zhuang This study tries to find the probability distributions of focal mechanisms in background seismicity and earthquake clusters in Japan by analyzing F-net data. To describe the probability distribution, each focal mechanism is discomposed as the result... more
Poster 216	GM	Displaced rocks as an indicator of ground motion during the 4 July 2019 M6.4 Ridgecrest earthquake Malinda Zuckerman, Colin Amos, Christopher Madugo, Austin Elliott, Albert Kottke, Christine Goulet, Xiaofeng Meng, Jacqueline Caplan-Auerbach Fragile geologic features, including rocks or rock formations displaced or toppled during earthquakes, provide insight into spatial extent and intensity of strong ground shaking. This study focuses on individual pebble and cobble sized clasts... more

The Southern California Earthquake Center is committed to providing a safe, productive, and welcoming environment for all participants. We take pride in fostering a diverse and inclusive SCEC community, and therefore expect all participants to abide by the SCEC Activities Code of Conduct.

Category:
Author:
Title:
Abstract:
Format:

Meeting Abstracts

IMPORTANT DATES

For Researchers

For The Media