← Back to Sessions

New Empirical Source Scaling Laws for Crustal Earthquakes Incorporating the Fault Dip Angle and Seismogenic Thickness Effects

Description: 

We developed new global source scaling laws for crustal earthquakes that include the effect of the fault dip angle and bottom depth of the seismogenic zone. The bottom-depth effect consists of a regional term and a normalized hypocenter depth term. In contrast to the commonly used scaling relations between moment magnitude (M), fault length (L), width (W), and area, we relate M to the aspect ratio (L/W) and to the fault area simultaneously to control the main behavior that the aspect ratio increases once the rupture width reaches the fault width limit. A global data set of finite-fault from multiple references, such as the Earthquake Source Model Database (SRCMOD) and several extra Taiwan events, was compiled for use in developing the source scaling relation for crustal earthquakes in this study. The scaling differences are physically related to the fault geometry but do not appear to depend on the rake angle. The scaling for the dataset can be captured very well by the proposed aspect-ratio scaling law with geometry-related effects, such as the magnitude-dependent dip and the bottom depth of the seismogenic zone. We used a bilinear relation to model the magnitude-area scaling law, and it generally behaved similarly to the scaling in previous area-M studies. Finally, the corresponding L and W scaling relations obtained by converting the area and aspect ratio to L and W showed good agreement with the previous regional scaling laws on average but provide better fault-specific application due to the inclusion of fault-specific dip angles and seismogenic depths.

Session: Earthquake Source Parameters: Theory, Observations and Interpretations

Type: Oral

Date: 4/18/2023

Presentation Time: 02:45 PM (local time)

Presenting Author: JyunYan Huang

Student Presenter: No

Invited Presentation: 

Authors