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yiheh@umich.edu
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- Creator:
- Huang, Yihe
- Description:
- Geological and geophysical observations reveal along-strike fault zone heterogeneity on major strike-slip faults, which can play a significant role in earthquake rupture propagation and termination. I present 2D dynamic rupture simulations to demonstrate rupture characteristics in such heterogeneous fault zone structure. The modeled rupture is nucleated in a damaged fault zone and propagates on a preexisting fault towards the zone of intact rocks. There is an intermediate range of nucleation lengths that only allow rupture to spontaneously propagate in the damaged fault zone but not in a homogeneous medium. I find that rupture with an intermediate nucleation length tends to stop when it reaches the zone of intact rocks, especially when the rupture propagation distance in the damaged fault zone is relatively short and when the damaged fault zone is relatively narrow or smooth in the fault-normal direction. Pronounced small-scale heterogeneity within the damaged fault zone also contributes to such early rupture termination. In asymmetric fault zones bisected by a bimaterial fault, rupture moving in the direction of slip of faster rocks tends to terminate under the same conditions as in symmetric fault zones, whereas rupture moving in the direction of slip of slower rocks can penetrate into the zone of intact rocks. Break-through rupture is allowed when a sufficiently-large asperity is located at the edge of the zone of intact rocks. The results suggest the along-strike fault zone heterogeneity can play a critical role in seismicity distribution. The data set contains multiple folders of simulation results from the SEM2DPACK that demonstrate the above findings. The folder name includes the model parameters in each simulation as explained in the README file. The Flt01_sem2d.data file in the folder documents the slip, slip rate and stresses from each simulation. The files are also explained in the manual of SEM2DPACK ( http://web.gps.caltech.edu/~ampuero/soft/users_guide_sem2dpack.pdf). Please refer to section 4.6 in the manual and use “sem2d_read_fault.m” in the POST folder of SEM2DPACK to plot the results.
- Keyword:
- Damaged fault zone, fault zone heterogeneity, earthquake rupture termination, and seismicity distribution
- Discipline:
- Science
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- Creator:
- Huang, Yihe (University of Michigan); De Barros, Louis (Université Côte d’Azur)
- Description:
- Numerous small and moderate injection-induced earthquakes have been recorded in North America, Europe and Asia. Here we present a detailed analysis about microearthquakes in an in-situ injection-induced earthquake experiment, which provides an unprecedented opportunity to investigate the mechanisms of induced earthquakes. Our analysis illuminates meter-scale earthquake sources distributed in a network of preexisting rock fractures. The majority of induced earthquakes in our analysis happened when injection pressure reached a peak, indicating a direct response of rock fractures to fluid pressure perturbation. But the relatively low ratio of stress drop to crustal strength reveals that a very small fraction of the crustal shear strength is released by earthquakes, supporting the previous notion that fluid injection induces large aseismic deformation during the experiment. and Citation for dataset: Huang, Y., De Barros, L. (2019). Seismograms of earthquake pairs in the injection experiment [Data set]. University of Michigan - Deep Blue.
- Keyword:
- Induced seismicity
- Citation to related publication:
- Huang, Y., De Barros, L., Cappa, F. (2019). Illuminating the Rupturing of Microseismic Sources in an Injection‐Induced Earthquake Experiment. Geophysical Research Letters, 46(16), 9563-9572. https://doi.org/10.1029/2019GL083856
- Discipline:
- Science