The mechanics of rupture propagation through fault bends during strike-slip earthquakes

Vanessa Herrera, Alba M. Rodriguez Padilla, Sophia White, & Michael E. Oskin

Published September 11, 2022, SCEC Contribution #12540, 2022 SCEC Annual Meeting Poster #174 (PDF)

Fault bends, or changes in fault strike, can inhibit rupture propagation and thus exert a primary control on rupture length, and, consequently, the final size of the earthquake. Therefore, investigating the mechanics of rupture propagation through bends is important for better constraining seismic hazard and potential earthquake magnitude maxima. Through analysis of breached and unbreached single and double bends, and their measured angles and lengths in thirty-one strike-slip earthquakes using the Fault Displacement Hazard Initiative (FDHI) rupture database, we revisit the role of fault bends in rupture propagation. We find that bends with an angle ≤ 30° are easily breached, allowing throughgoing rupture in most of our case studies. Bends with angles >60 degrees always inhibit rupture propagation, though we only sample a small number of bends > 50 degrees. Additionally, we observe that the vast majority of our breached double bends had along-strike lengths ≤ 2km. The observed fault bend constraints highlight the vital role these geometric complexities play in rupture propagation in strike-slip fault networks.

Citation
Herrera, V., Rodriguez Padilla, A. M., White, S., & Oskin, M. E. (2022, 09). The mechanics of rupture propagation through fault bends during strike-slip earthquakes. Poster Presentation at 2022 SCEC Annual Meeting.

Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)