Aftershock productivity of large megathrust earthquakes: regional variations and influence of mainshock source parameters

Nadav Wetzler, Emily E. Brodsky, & Thorne Lay

Published July 25, 2016, SCEC Contribution #6331, 2016 SCEC Annual Meeting Poster #169

Aftershock productivity is observed to increase with mainshock magnitude following a well-defined relationship for any given region. However, variation of this scaling relationship is still poorly characterized. We focus on variations of aftershock productivity of large (MW ≥ 7.0) circum-Pacific megathrust earthquakes within the past 25 years. We investigate how aftershock productivity varies regionally and with respect to mainshock source parameters determined by finite-fault rupture model inversions. Aftershock productivity is higher for islands arcs of the western circum-Pacific than for continental arcs of the eastern circum-Pacific. Events with larger static stress-drop tend to produce fewer aftershocks than comparable magnitude events with lower stress-drop. The regional trend may reflect differences in fault susceptibility between island arcs and continental arcs, whereas the stress-drop behavior may imply near-total stress-drop release for some events.

Key Words
aftershock productivity, static stress-drop, megathrust earthquakes

Citation
Wetzler, N., Brodsky, E. E., & Lay, T. (2016, 07). Aftershock productivity of large megathrust earthquakes: regional variations and influence of mainshock source parameters. Poster Presentation at 2016 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology