Dynamic triggering of creep events in the Salton Trough, Southern California by regional M≥5.4M≥5.4 earthquakes constrained by geodetic observations and numerical simulations
McGuire, Jeffrey J.
MetadataShow full item record
KeywordDynamic triggering; Creep events; Shallow frictional heterogeneity; Amplitude threshold; Superstition Hills Fault
Since a regional earthquake in 1951, shallow creep events on strike-slip faults within the Salton Trough, Southern California have been triggered at least 10 times by M ≥ 5.4 earthquakes within 200 km. The high earthquake and creep activity and the long history of digital recording within the Salton Trough region provide a unique opportunity to study the mechanism of creep event triggering by nearby earthquakes. Here, we document the history of fault creep events on the Superstition Hills Fault based on data from creepmeters, InSAR, and field surveys since 1988. We focus on a subset of these creep events that were triggered by significant nearby earthquakes. We model these events by adding realistic static and dynamic perturbations to a theoretical fault model based on rate- and state-dependent friction. We find that the static stress changes from the causal earthquakes are less than 0.1 MPa and too small to instantaneously trigger creep events. In contrast, we can reproduce the characteristics of triggered slip with dynamic perturbations alone. The instantaneous triggering of creep events depends on the peak and the time-integrated amplitudes of the dynamic Coulomb stress change. Based on observations and simulations, the stress change amplitude required to trigger a creep event of 0.01 mm surface slip is about 0.6 MPa. This threshold is at least an order of magnitude larger than the reported triggering threshold of non-volcanic tremors (2-60 KPa) and earthquakes in geothermal fields (5 KPa) and near shale gas production sites (0.2-0.4 kPa), which may result from differences in effective normal stress, fault friction, the density of nucleation sites in these systems, or triggering mechanisms. We conclude that shallow frictional heterogeneity can explain both the spontaneous and dynamically triggered creep events on the Superstition Hills Fault.
Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 427 (2015): 1-10, doi:10.1016/j.epsl.2015.06.044.
Showing items related by title, author, creator and subject.
Detection of transcriptional triggers in the dynamics of microbial growth: application to the respiratorily versatile bacterium Shewanella oneidensis Beg, Qasim K.; Zampieri, Mattia; Klitgord, Niels; Collins, Sara B.; Altafini, Claudio; Serres, Margrethe H.; Segre, Daniel (Oxford University Press, 2012-05-25)The capacity of microorganisms to respond to variable external conditions requires a coordination of environment-sensing mechanisms and decision-making regulatory circuits. Here, we seek to understand the interplay between ...
The dynamic relationships between the three events that release individual Na+ ions from the Na+/K+-ATPase Gadsby, David C.; Bezanilla, Francisco; Rakowski, Robert F.; De Weer, Paul; Holmgren, Miguel (Nature Publishing Group, 2012-02-14)Na+/K+ pumps move net charge through the cell membrane by mediating unequal exchange of intracellular Na+ and extracellular K+. Most charge moves during transitions that release Na+ to the cell exterior. When pumps are ...
Extreme climate events and individual heterogeneity shape life-history traits and population dynamics Jenouvrier, Stephanie; Peron, Clara; Weimerskirch, Henri (Ecological Society of America, 2015-11)Extreme climatic conditions and their ecological impacts are currently emerging as critical features of climate change. We studied extreme sea ice condition (ESIC) and found it impacts both life-history traits and population ...