scholarly journals Dynamic Rupture Scenarios in the Brawley Seismic Zone, Salton Trough, Southern California

2019 ◽  
Vol 124 (4) ◽  
pp. 3680-3707 ◽  
Author(s):  
C. Kyriakopoulos ◽  
D. D. Oglesby ◽  
T. K. Rockwell ◽  
A. J. Meltzner ◽  
M. Barall ◽  
...  
Keyword(s):  
Southern California ◽  
Seismic Zone ◽  
Dynamic Rupture ◽  
Salton Trough

scholarly journals Durmid ladder structure and its implications for the nucleation sites of the next M >7.5 earthquake on the San Andreas fault or Brawley seismic zone in southern California

Lithosphere ◽  
2018 ◽  
Vol 10 (5) ◽  
pp. 602-631 ◽  
Author(s):  
Susanne U. Jänecke ◽  
Daniel K. Markowski ◽  
James P. Evans ◽  
Patricia Persaud ◽  
Miles Kenney
Keyword(s):  
Southern California ◽  
San Andreas Fault ◽  
Seismic Zone ◽  
Ladder Structure ◽  
San Andreas ◽  
Nucleation Sites

Quantifying preparation process of large earthquakes: Damage localization and coalescent dynamics

2020 ◽  
Author(s):  
Ilya Zaliapin ◽  
Yehuda Ben-Zion
Keyword(s):  
Cluster Size ◽  
Southern California ◽  
Time Window ◽  
Oriented Graph ◽  
Seismic Zone ◽  
Average Cluster Size ◽  
Emission Data ◽  
Aftershock Sequences ◽  
Large Earthquakes ◽  
Average Cluster

<p>We attempt to track and quantify preparation processes leading to large earthquakes using two complementary approaches. (a) Localization of brittle deformation manifested by evolving fractional volume with seismic activity, and (b) Coalescence of earthquakes into clusters. We analyze seismicity catalogs from Southern California (SoCal), Parkfield section of the San Andreas Fault (SAF), and region around the 1999 Izmit and Duzce earthquakes in Turkey.</p><p>Localization of deformation is estimated using the Receiver Operating Characteristic (ROC) approach. Specifically, we consider temporal evolution of the fractional volume 0 ≤ V(q) ≤ 1 occupied by the fraction 0 ≤ q ≤ 1 of active voxels with mainshocks. We also consider the localization of the spatial intensity of mainshocks within a sliding time window with respect to the time-averaged distribution, quantified by Gini coefficient G. The significance of the results is assessed using reshuffled catalogs. Analysis within the rupture zones of large earthquakes indicate decrease of V(q) and increase of G (increased localization) prior to the Landers (1992, M7.3), El Mayor-Cucapah (2010, M7.2), Ridgecrest (2019, M7.1), and Duzce (1999, M7.2) mainshocks. We also observe ongoing damage production by the background seismicity around these rupture zones several years before their occurrences. In contrast, we observe increase of V(q) and decrease of G prior to the Parkfield (2004, M6.0) mainshock in the creeping section of the SAF. Next, we examine the quasi-linear region in the Eastern part of Southern California around the Imperial fault, Brawley seismic zone, southern SAF and Eastern California Shear Zone. We document four cycles of background localization, measures by V(q) and G, well aligned in time with the largest events in the region: Landers, Hector Mine, El Mayor-Cucapah, and Ridgecrest. The coalescence process is represented by a time-oriented graph that connects each earthquake in the examined catalog to all earlier earthquakes at the earthquake nearest-neighbor proximity below a specified threshold. We examine the size of the clusters that correspond to low thresholds, and hence represent active clustering episodes. We document increase of the average cluster size prior to the Landers, El Mayor-Cucapah, Ridgecrest and Duzce mainshocks, and decrease of the average cluster size prior to the Parkfield mainshock.</p><p>The results of our complementary localization and coalescent analyses consistently indicate progressive localization of damage prior to the largest earthquakes on non-creeping faults and de-localization on the creeping Parkfield section of SAF. These findings are consistent with analysis of acoustic emission data. The study is a step towards developing methodology for analyzing the dynamics of seismicity in relation to preparation processes of large earthquakes, which is robust to spatio-temporal fluctuations associated with aftershock sequences, data incompleteness and common catalog errors.</p>

WHAT DO WE KNOW ABOUT LATE CENOZOIC LANDSCAPE EVOLUTION AT THE NORTHWEST HEAD OF THE SALTON TROUGH, SOUTHERN CALIFORNIA?

2016 ◽  
Author(s):  
Jonathan C. Matti ◽  
◽  
Katherine J. Kendrick ◽  
Robert E. Powell ◽  
Shannon A. Mahan ◽  
...  
Keyword(s):  
Southern California ◽  
Landscape Evolution ◽  
Late Cenozoic ◽  
Salton Trough

Mechanical Models Suggest Fault Linkage through the Imperial Valley, California, U.S.A.

2019 ◽  
Vol 109 (4) ◽  
pp. 1217-1234 ◽  
Author(s):  
Jacob H. Dorsett ◽  
Elizabeth H. Madden ◽  
Scott T. Marshall ◽  
Michele L. Cooke
Keyword(s):  
Southern California ◽  
Slip Rate ◽  
Fault Slip ◽  
Surface Strain ◽  
Plate Motion ◽  
Seismic Zone ◽  
Rate Data ◽  
Imperial Valley ◽  
Cerro Prieto

Abstract The Imperial Valley hosts a network of active strike‐slip faults that comprise the southern San Andreas fault (SAF) and San Jacinto fault systems and together accommodate the majority of relative Pacific–North American plate motion in southern California. To understand how these faults partition slip, we model the long‐term mechanics of four alternative fault networks with different degrees of connectivity through the Imperial Valley using faults from the Southern California Earthquake Center Community Fault Model version 5.0 (v.5.0). We evaluate model results against average fault‐slip rates from the Uniform California Earthquake Rupture Model v.3 (UCERF3) and geologic slip‐rate estimates from specific locations. The model results support continuous linkage from the SAF through the Brawley seismic zone to the Imperial and to the Cerro Prieto faults. Connected faults decrease surface strain rates throughout the region and match more slip‐rate data. Only one model reproduces the UCERF3 rate on the Imperial fault, reaching the lower bound of 15  mm/yr. None of the tested models reproduces the UCERF3 preferred rate of 35  mm/yr. In addition, high‐strain energy density rates around the Cerro Prieto fault in all models suggest that the UCERF3 preferred rate of 35  mm/yr may require revision. The Elmore Ranch fault‐slip rate matches the UCERF3 rate only in models with continuous linkage. No long‐term slip‐rate data are available for the El Centro and Dixieland faults, but all models return less than 2  mm/yr on the El Centro fault and 3.5–9.6  mm/yr on the Dixieland fault. This suggests that the Dixieland fault may accommodate a significant portion of plate‐boundary motion.

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