Practice : dynamic rupture in 2D and 2.5D Huihui Weng Jean-Paul Ampuero
Goals • Learn to simulate dynamic rupture model • Explore the effects of fault heterogeneities on dynamic ruptures • Discussion: seismology problems
2D and 2.5D numerical codes Download from GitHub
2D and 2.5D numerical codes Download from GitHub
MATLAB code semlab ----- run it directly Fortran code sem2dpack ----- installation is simple ----- simulation is fast
Model parameters LX or LX/2 Discretized size S wave speed Density LY Stations Static friction coe ffj cient τ Dynamic friction coe ffj cient Frictional fault Normal stress τ s Shear stress Slip-weakening distance τ 0 Dc τ d Slip
Seismogenic width W (3 equations) x 1 Reduce to 1 equation x 2 x 3 Aseismic region Aseismic region Sin(k 3 x 3 ) Slip profile Slip approximation Aseismic region Aseismic region Seismogenic width W
Tutorial of semlab Tutorial of sem2dpack
How to run semlab? cd ${work_dir}/semlab-master/SEMLAB matlab & open this file from matlab: sem2d_eq_dyn_tutorial.m
Parameter setup in semlab
Result presentation (figure1)
Result presentation (figure2)
Result presentation (figure3) Cohesive tail Stopping phase Tip Stopping phase
Result presentation (figure3) Cohesive tail Stopping phase Tip Stopping phase Definition of tip: Slip Slip rate > threshold Slip rate Definition of cohesive tail: Stress Slip = Dc Tip Tail of cohesive zone
Result presentation (figure4)
STF and its spectrum (final)
STF and spectra
Add a heterogeneity
STF comparison
Models to test Model 1 Uniform fault Barrier Ø Heterogeneity can be initial stress or Dc abrupt stop Ø Question: what are the Model 2 differences of STF and spectrum? Barrier Uniform fault Ø Discussion: what are the gradually stop differences between 2D and 2.5D models? Model 3 Rough fault Barrier abrupt stop
Discussion Apple to apple Model 1 Uniform fault Barrier Ø model 1 vs. model 2 abrupt stop Ø model 1 vs. model 3 Model 2 Barrier Uniform fault Ø 2D vs. 2.5D gradually stop Model 3 Rough fault Barrier abrupt stop
Discussion Ø model 1 vs. model 2
Discussion Ø model 1 vs. model 3
Discussion Ø 2D vs. 2.5D
Models to test Model 4 Ø Heterogeneity is initial stress Uniform fault Ø Question: do these heterogeneities increase Initial stress Previous ruptured region high-frequency radiation? Model 5 Ø Discussion: what parameters may control the high- Uniform fault frequency radiation? Dc Steps
Discussion Apple to apple Model 4 Ø model 1 vs. model 4 Uniform fault Initial stress Previous ruptured region Ø model 1 vs. model 5 Model 5 Ø 2D vs. 2.5D Uniform fault Dc Steps
Discussion Ø model 1 vs. model 4
Discussion Ø model 1 vs. model 5
Tutorial of SEMLAB Tutorial of sem2dpack
Installation of sem2dpack
How to run sem2dpack? cd ${work_dir}/sem2dpack- 25D/EXAMPLES/2.5D_inplane open this file by vim or other method: vi Par.inp
Parameter setup in sem2dpack
Parameter setup in sem2dpack
How to present results? cd ${work_dir}/sem2dpack-25D/POST open the script by MATLAB: create_movie.m run it by MATLAB
Discussion Ø Find seismic phases, such as P wave front, S wave, Rayleigh wave, etc. Ø What parameters may control the formation of supershear rupture?
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