Meeting Abstracts

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 form below to search and view all poster and invited talk abstracts submitted to this meeting.

Results 151-200 of 320

SCEC ID	Category	Title and Authors	SCEC Award
Poster 144	SAFS	Multi-cycle Dynamics of the San Andreas and San Jacinto Faults in Southern California Dunyu Liu, Benchun Duan Natural fault systems have geometric complexities at various scales. Earthquake ruptures may halt at or propagate through these complexities, especially macroscopic ones (so called ‘earthquake gates’), depending on fault geometries and fault stress/... more	19238
Poster 056	Seismology	Ambient Noise Love Wave Attenuation Inversion using the LASSIE Array through Los Angeles Basin Xin Liu, Gregory Beroza We present a simple and efficient method to extract the attenuation quality factors using the ambient seismic noise data from the LASSIE linear array located at the southeastern edge of the Los Angeles basin. The three-component LASSIE array spans ~... more
Poster 210	Geodesy	Imaging tectonic and anthropogenic processes using ALOS-2 and Sentinel-1 InSAR Zhen Liu, Paul Lundgren, Cunren Liang The improved spatiotemporal resolution of surface deformation from recent satellite sensors such as Sentinel-1 (S-1) and ALOS-2 provides a great opportunity to better constrain and understand both tectonic and non-tectonic processes. In this study,... more
Poster 037	EFP	Assessing declustering methods in Hawaii for probabilistic seismic hazard assessment Andrea Llenos, Andrew Michael, Morgan Moschetti, Charles Mueller, Mark Petersen, Allison Shumway Probabilistic seismic hazard assessments often use background earthquake rate estimates determined from a spatially smoothed declustered earthquake catalog. Declustering aims to remove aftershocks from catalogs, leaving behind a rate of independent... more
Poster 279	Ridgecrest	Preliminary dynamic rupture simulations of the July 2019 M6.4 and M7.1 Ridgecrest, California, earthquakes Julian Lozos, Ruth Harris The primary events of the 2019 Ridgecrest earthquake sequence were a M6.4 earthquake with left-lateral surface rupture that also produced aftershocks on a conjugate right-lateral fault, followed 34 hours later by a M7.1 earthquake that ruptured the... more
Poster 171	FARM	Slip transient pattern changes: external perturbation or intrinsic interaction with earthquakes Yingdi Luo, Zhen Liu Advances in geodetic techniques enable us to detect slow-slip events (SSE) and shallow fault creeping events (part of shallow SSE) with improving accuracy and coverage. Recent observations reveal intriguing changes of SSE behavior before and/or... more
Poster 148	FARM	Validation of Broadband Ground Motion from Dynamic Rupture Simulations: towards better characterizing seismic hazard for engineering applications Shuo Ma, Kyle Withers, Jean-Paul Ampuero, Luis Dalguer, Yongfei Wang, Christine Goulet In areas where observed ground motion data is lacking (e.g. near-source), seismicity is infrequent, or where geologic structures complicate seismic wave propagation, simulations provide an approach to improving the accuracy of ground motion... more	19077
Poster 067	Seismology	Investigation of the Yorba Linda Trend using earthquake relocation based on waveform cross-correlation Kyle Macy, Jascha Polet The Yorba Linda Trend was defined in the early 1990s as a southwest trending series of earthquakes that starts near the center of the Chino Hills, transects the Whittier Fault and extends into the southeastern Los Angeles Basin. The Trend... more
Poster 268	Ridgecrest	Prospective and Pseudo-prospective Aftershock Forecasts After the July 2019 M6.4 Searles Valley and M7.1 Ridgecrest Earthquakes Simone Mancini, Margarita Segou, Tom Parsons, Maximilian Werner On 4 July 2019, a M6.4 earthquake hit southern California west of Searles Valley, activating a system of NE-SW oriented left-lateral and NW-SE trending right-lateral strike slip faults. 34 hours later, a M7.1 earthquake struck near Ridgecrest,... more
Poster 059	Seismology	Intra-slab stress field and waveform modeling to determine velocity structure of the Indoburman Range Patcharaporn Maneerat, Doug Dreger, Roland Bürgmann The Indoburman Range (IBR), was formed due to the India-Eurasia collision since the Paleogene, is a highly oblique subduction zone. The dominance of observed strike-slip and intra-slab earthquakes brings into question the current activity of... more
Poster 045	Seismology	On The Measurement Of Seismic Travel-Time Changes In The Time-Frequency Domain With Wavelet Cross-Spectral Analysis Shujuan Mao, Aurelien Mordret, Michel Campillo, Hongjian Fang, Rob van der Hilst The spatial distribution of temporal variations in seismic wavespeed is key to understanding the sources and physical mechanisms of various geophysical systems. The imaging of wavespeed changes requires accurate measurements of travel-time delays... more
Poster 205	Geodesy	Dynamically Triggered Changes in Interface Coupling in Southern Cascadia Kathryn Materna, Noel Bartlow, Aaron Wech, Charles Williams, Roland Bürgmann The Mendocino Triple Junction (MTJ) is a rapidly deforming plate boundary zone at the intersection of the San Andreas fault, the Cascadia Subduction Zone (CSZ), and the Mendocino Fault Zone. Earthquake cycle deformation in this region results in... more
Poster 133	SAFS	Is the Mission Creek Fault in the San Gorgonio Pass region of southern California a long-abandoned strand of the San Andreas Fault? Or is it a major player in the San Andreas Fault’s late Quaternary strain budget? Jonathan Matti, Katherine Kendrick, Doug Yule, Richard Heermance The San Andreas Fault (SAF) zone in the San Gorgonio Pass (SGP) region is geologically and geomorphically more complex than perhaps anywhere else in southern California. Here, the zone consists of at least six separate strands that, acting together... more
Poster 248	Ridgecrest	Strong Ground Motions from 2019 Ridgecrest Earthquake Sequence Mainshocks Silvia Mazzoni, Tadahiro Kashida, Pengfei Wang, Sean Ahdi, Yousef Bozorgnia, Jonathan Stewart The Ridgecrest Earthquake sequence included a M6.4 foreshock on 4 July 2019 and a M7.1 mainshock event on 5 July 2019. These events occurred in the Eastern California Shear Zone, near Indian Wells Valley, south of China Lake and west of Searles... more
Poster 099	Geology	Late Pleistocene rates of folding and faulting in the western Transverse Ranges, California, from reconstruction and luminescence dating of the late Pleistocene Orcutt formation Ian McGregor, Nate Onderdonk The onshore Santa Maria Basin in central California is an inverted basin with up to 9 kilometers of estimated shortening that has folded, faulted, and uplifted Miocene through Quaternary rocks. Previous studies have used subsurface data from oil... more
Poster 225	Ridgecrest	Resolving Ridgecrest complex deformation modes characterized with differential LiDAR topography Emmons McKinney, Adam Wade, Christopher Madugo, Ozgur Kozaci Pre- and post-earthquake Airborne LiDAR-derived point clouds with a density of ~26 points/m2 were collected by Pacific Gas and Electric Company (PG&E) along sections of the M6.4 July 4 and M7.1 July 5 2019 surface ruptures and mapped Quaternary... more
Poster 290	GM	Preliminary survey of fragile geological features for use as ground motion constraints, southern Oregon Devin McPhillips, Katherine Scharer Fragile geological features, which are extant on the landscape but vulnerable to earthquake ground shaking, provide rare geological constraints on the intensity of prior shaking. These features may be especially valuable in regions such as the... more
Poster 082	Seismology	A Systematic Investigation into Dynamic and Delayed Earthquake Triggering in a Seismically Hazardous Himalayan Fault Segment Manuel Mendoza, Bo Li, Abhijit Ghosh, Shyam Rai Observations of remote earthquake triggering by the passage of teleseismic waves is well-documented [e.g. Prejean et al., 2015; Ghosh et al., 2009]; however, the mechanisms driving both the “dynamic” and “delayed” facets of this phenomenon remain... more
Poster 023	GM	Fully Nonergodic Ground Motion Models in Central California Using NGA-West2 and SCEC CyberShake Datasets Xiaofeng Meng, Christine Goulet, Kevin Milner, Scott Callaghan A key input to probabilistic seismic hazard analyses (PSHA) is the total standard deviation of the misfits between ground motion observations and the median ground motion models (GMMs, a.k.a GMPEs), commonly known as σtot. The most promising way to... more
Poster 109	Geology	STRATIGRAPHIC AND GEOCHRONOLOGIC CONSTRAINTS ON TIME-SPACE PATTERNS OF LATEST QUATERNARY SURFACE RUPTURES ON THE EASTERN PINTO MOUNTAIN AND SOUTHERN MESQUITE LAKE FAULT ZONES NEAR TWENTYNINE PALMS, SOUTHERN CALIFORNIA Christopher Menges, Shannon Mahan Recent surficial geologic mapping and new luminescence dating provide constraints on the time-space patterns of latest Quaternary surface ruptures along the E Pinto Mountain fault (PMf) and S Mesquite Lake fault (MLf) near Twentynine Palms in... more
Poster 228	Ridgecrest	OR-Corr a New Outlier-Resistant Image Correlation Method: Examples of Surface Deformation and Complex Fracturing from the 2019 Ridgecrest Earthquake Sequence Imaged by High-resolution Optical and Radar Imagery Chris Milliner, Andrea Donnellan, Rui Chen, Robert Zinke, Xiaohua Xu, Alex Morelan, Timothy Dawson, Christopher Madugo, James Dolan, Alexandra Sarmiento, Yousef Bozorgnia, Adnan Ansar The 2019 Ridgecrest earthquake sequence, CA, involved a Mw 6.4 foreshock on July 4th and the Mw 7.1 mainshock that occurred 34 hours later located ~12 km to the north. This sequence resulted in a complex array of surface fractures that were measured... more	19222
Poster 271	Ridgecrest	Operational earthquake forecasting during the M6.4 Searles Valley and M7.1 Ridgecrest sequence using the UCERF3-ETAS model—evaluation and lessons learned Kevin Milner, Edward Field, William Savran, Thomas Jordan, Morgan Page, Maximilian Werner By 11:10 am on July 4, 2019 (36 minutes after the M6.4 Searles Valley earthquake), the first UCERF3-ETAS aftershock simulations were running at the University of Southern California’s High-Performance Computing Center. UCERF3-ETAS (Field et al.,... more	19227
Poster 154	FARM	Rheology of the Borrego Springs Shear Zone segment of the Eastern Peninsular Ranges Mylonite Zone: implications for the development of the Community Rheology Model Elena Miranda, Miguel Zamora-Tamayo, Joshua Schwartz, Jennifer Bautista, Sinan Akciz We define and constrain the rheology of mylonites in the Eastern Peninsular Ranges Mylonite Zone (EPRMZ) in order to place realistic constraints on the strength of ductile shear zones as part of the development of a Community Rheology Model (CRM)... more	19023
Poster 022	GM	An empirical- and simulation-based ground-motion model for Southern California Morgan Moschetti, Eric Thompson, Nicolas Luco, Thomas Jordan, Peter Powers, Allison Shumway, Mark Petersen, Robert Graves, Scott Callaghan, Christine Goulet, Kevin Milner, Philip Maechling, Feng Wang, John Rekoske We report progress on the development of a long-period (T>=2 s) ground-motion model (GMM) for Southern California based on an empirical GMM and the CyberShake simulations. Ground-motion prediction within sedimentary basins is hampered by complex... more
Poster 265	Ridgecrest	Visualising the Ridgcrest Earthquakes using Wavefield Reconstruction Jack Muir, Zhongwen Zhan The high station density of the Southern California Seismic Networks gives us the opportunity to treat earthquake wavefields as unified objects rather than as a collection of individual seismograms, allowing robust computation of useful higher order... more
Poster 235	Ridgecrest	Mitigating the Effect of the Ridgecrest Earthquakes on the USGS’s Automated Analysis of Global Positioning System Data Jessica Murray, Jerry Svarc The two largest earthquakes of the Ridgecrest sequence caused significant coseismic and ongoing postseismic displacement at regional GPS stations. Coseismic offsets exceed 0.5 meter at near-fault stations, and exceed 5 millimeters at stations ~240... more
Poster 003	GM	Shallow crustal heterogeneity in Southern California estimated from earthquake coda waves Nori Nakata, Hongjian Fang, Malcolm White, Arben Pitarka High-frequency scattered waves contain important information to reveal small-scale structure such as heterogeneities of velocities and attenuation, which should be considered and included for high-frequency ground motion modeling. Here, we are... more	19174
Poster 294	EEII	How will the risk and losses change by using the newest Uniform California Earthquake Rupture Forecast models in Catastrophe Modeling? NEGAR NAZARI The Earthquake Catalog is the core of the loss calculation. Currently, as far as I know, only the “UCERF3-time independent” model is being used in most of Catastrophe modeling evaluations for California. Obviously, it takes time for industry to... more
Poster 017	GM	Ground motion simulation validation with explicit uncertainty incorporation for small magnitude earthquakes in the Canterbury region Sarah Neill, Robin Lee, Brendon Bradley This study explicitly investigates uncertainties in physics-based ground motion simulation validation for earthquakes in the Canterbury region. The simulations utilize the Graves and Pitarka (2015) hybrid methodology, with separately quantified... more
Poster 310	CXM	Full Waveform Seismic Tomography for geophysical velocity model in Canterbury region based on the Adjoint-Wavefield method Trung Dung Nguyen, Robin Lee, Alan Juarez, Brendon Bradley In this paper we apply Full Waveform Tomography (FWT) based on the Adjoint-Wavefield (AW) method to iteratively invert a 3-D geophysical velocity model for the Canterbury region (Lee, 2017). The seismic wavefields was generated using numerical... more
Poster 323	CXM	Continued Updates, Expansion and Improvements to the Community Fault Model (CFM version 5.3) Craig Nicholson, Andreas Plesch, Christopher Sorlien, John Shaw, Scott Marshall, Egill Hauksson The Community Fault Model (CFM) is one of the most mature modeling efforts within SCEC, yet it remains critical that the CFM be continually evaluated, updated and improved to more effectively support the wide range of research activities targeted by... more	19031, 19102
Poster 009	GM	Simulation of elastic waves in the presence of topography using a curvilinear staggered grid finite difference method Ossian O'Reilly, Alexander Breuer, Yifeng Cui, Christine Goulet, Kim Olsen, Daniel Roten, Guillaume Thomas-Collignon, Te-Yang Yeh We are in the process of incorporating topography into the anelastic wave propagation code AWP. This code is used within SCEC’s Cybershake project and High-F simulation activities. AWP solves the elastic wave equation by staggering velocity and... more
Poster 156	FARM	The role of lithology in fault re-strengthening: A case study of the 2011 Prague, Oklahoma induced earthquake sequence Kristina Okamoto, Heather Savage, Kathleen Keranen, Brett Carpenter Faults dynamically weaken during earthquakes and strengthen between them. Thus, fault healing is an important part of the seismic cycle, which depends on in situ conditions as well as lithology. Understanding how faults re-strengthen after... more
Poster 049	Seismology	Towards identifying its seismic observables in models of coseismic off-fault damage Kurama Okubo, Harsha Bhat, Esteban Rougier, Marine Denolle Coseismic off-fault damage is dynamically activated during earthquake ruptures due to stress concentration in the off-fault medium. The contribution of off-fault damage to the radiation and overall energy budget is non-negligible, and thus important... more
Poster 126	Geology	Paleoseismology of the largest earthquakes from the Himalayan front Koji Okumura, Javed Malik, Prakash Pokhrel, Soma Sapkota A lot of new paleoseismological data and new interpretations of past data on the rapture history of the Himalayan frontal thrusts have been presented since 2015 Gorkha earthquake. There are plenty of exciting findings and interesting ideas that may... more
Poster 176	FARM	Slip evolution across geometric barrier during the 2018 Palu Indonesia earthquake Ryo Okuwaki, Yuji Yagi How does a slip follow earthquake-rupture front propagating faster than at a local shear-wave velocity (supershear speed)? How does a supershear-rupture front go across geometric discontinuity in a fault system? Resolving in detail such a complex... more
Poster 136	SAFS	Using UAV-mounted LiDAR surveys to investigate potential slip rate sites along the northernmost San Jacinto fault zone near its junction with the San Andreas fault in the Cajon Pass area, California Nate Onderdonk, Drake Kerr, Paula Figueiredo Paleoseismic data, slip-rate data, and modeling suggest that slip transfer between the San Andreas and San Jacinto faults may occur during simultaneous rupture of the two faults in the Cajon Pass area. To test this idea, slip-rate measurements and... more	18124
Poster 145	FARM	Does a damaged fault zone mitigate the near-field landslide risk during supershear earthquakes?—Application to the 2018 magnitude 7.5 Palu earthquake Elif Oral, Huihui Weng, Jean-Paul Ampuero The 2018 Mw 7.5 Palu earthquake ruptured a strike-slip fault with a length of 150 km and struck the city of Palu severely by triggering many catastrophic phenomena in the proximity of the fault. Devastating tsunamis in the Palu Bay are triggered... more
Poster 078	Seismology	A Percolation Model for Induced Seismicity: An Avalanche Burst Model for Induced b-Value Seismicity. Ronaldo Ortez, John Rundle In the interest of being able to reproduce the kinds of fracture networks produced during hydraulic fracking, we use percolation models which, near criticality, seem to produce the kinds of networks consistent with those produced during fracking. To... more
Poster 219	Ridgecrest	Fault slip distribution along the southern 15 km of the M7.1 Ridgecrest earthquake surface rupture Salena Padilla, Sinan Akciz, Alexandra Hatem, James Dolan, Ridgecrest Rupture Mapping Group A pair of large earthquakes struck the Searles Valley, California area on July 4 and 5, 2019. The July 5, M7.1 earthquake northeast of Ridgecrest, CA, ruptured bilaterally along an ~50 km long, right-lateral, fault zone striking NW-SE. We followed... more
Poster 028	EFP	Explaining the paleo-event hiatus in California Morgan Page, Edward Field, Kevin Milner, Nicholas van der Elst There has been a notable absence of large earthquakes in the last century in California, particularly on the highest slip-rate faults. This lull was noted by Jackson (2014), who argued that the observed data precluded Poissonian or lognormal... more
Poster 047	Seismology	Near-Surface Structure Constrained Using Body-Wave Polarization Sunyoung Park, Victor Tsai, Miaki Ishii Body-wave polarization is sensitive to properties immediately beneath a seismic instrument, and has been demonstrated to be effective at estimating the near-surface P- and S-wave speeds (Park & Ishii, 2018*). In this presentation, we discuss... more
Poster 077	Seismology	The Guy-Greenbrier seismic sequence revisited with deep learning Yongsoo Park, Mostafa Mousavi, Weiqiang Zhu, William Ellsworth, Gregory Beroza The emerging deep-learning-based algorithms for earthquake detection and phase arrival time picking have shown to be promising replacements for traditional methods such as STA/LTA and template matching. We revisited the Guy-Greenbrier, Arkansas,... more
Poster 245	Ridgecrest	Source, Site and Path Characterization of the July 2019 M7.1 and M6.4 Ridgecrest Earthquake Sequence Grace Parker, Annemarie Baltay, Eric Thompson, John Rekoske, Dan McNamara The 2019 July 5 M7.1 Ridgecrest, California earthquake generated peak ground motions in excess of 50% g and 60 cm/s near the fault and was recorded on over 700 local and regional seismic stations across California and eastern Nevada. In addition,... more
Poster 215	Geodesy	Tools for GNSS application to tectonics Jay Parker, Michael Heflin, Andrea Donnellan We propose a common set of tools for regional GNSS time series analysis. To retrieve regional time-limited sets of time series for earthquakes and other phenomena simple scripting elements reduce the varieties of center-specific formats to a... more
Poster 305	CEO	The Future of the SCEC Community Information System Edric Pauk, Tran Huynh, Mei-Hui Su, Philip Maechling SCEC provides scientists with collaborative, computing and data management facilities to support research collaborations, project administration, education and outreach programs, and advanced computational science. The SCEC Community Information... more
Poster 107	Geology	Paleoseismic Results from the Christmas Canyon West Site, Central Garlock Fault, Searles Valley, California Kyle Peña, Sally McGill, Ed Rhodes, James Dolan, Nathan Brown, Bryan Castillo, Alexandra Hatem, Sourav Saha, Robert Zinke In this study, a paleoseismic trench with limited age constraints that was previously excavated in 1990 across the central Garlock Fault west of Christmas Canyon, in Searles Valley, California, was reopened to take advantage of new advances in... more
Poster 239	Ridgecrest	Rheological implications of post-seismic deformation following the 2019 Ridgecrest Earthquakes Camilla Penney, Jean-Philippe Avouac Large earthquakes provide an opportunity to probe the rheology of the lithosphere and upper asthenosphere. The 2019 Ridgecrest earthquakes occurred in an area which may have significantly heterogeneous rheological properties, due to its proximity to... more
Poster 285	Seismology	Field Volunteers for the Los Angeles BASIN Seismic Experiment – Phase IV Patricia Persaud, Robert Clayton, Marine Denolle, Jascha Polet In mid-November 2019, we will launch the fourth and final phase of the BASIN seismic deployments in the greater Los Angeles area. We are seeking further volunteers to help make the deployment of an additional 262 compact seismic units called nodes... more	19033, 18029
Poster 137	SAFS	Using Ground-based Magnetics, VLF, and DC Resistivity to Examine Faulting at the San Andreas Oasis, Dos Palmas Preserve Stacey Petrashek, Nathan Pulver, Raul Contreras, Drew Faherty, Jascha Polet The San Andreas Oasis is located northeast of the Salton Sea near the convergence of several faults including the Hidden Spring and Powerline Faults, traces of which are mapped along a series of oases, seeps, and springs. Due to declining water... more

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