Earthquake Catalog Completeness Analysis for California and Nevada

Session: Earthquake Source Parameters: Theory, Observations and Interpretations [Poster]
Type: Poster
Date: 4/30/2020
Time: 08:00 AM
Room: Ballroom
Description: 

We analyze the earthquake catalog completeness for declustered M≥4 earthquakes in California and Nevada to improve the statistical analyses required for earthquake hazard assessments. For large magnitudes, M≥6.0, the catalog completeness has been traced back to 1850 based on historical documentation, while for smaller magnitudes the catalog completeness times are reliant on the temporal and spatial distribution of instrumental recordings. Given the significance of catalog completeness in studies of seismicity and earthquake source processes, we reexamine the catalog using: (1) a method assuming seismicity is steady-state and completeness levels may be detected based on temporal changes observed state-wide and (2) a method that assesses the historical seismic network detectability thresholds. In the first approach, a sharp fall-off of a state-wide steady-state average is considered to be caused by missing events in the catalog. In the second approach, the completeness of the catalog depends on the earthquake detection limits of the seismic network through historical times. We use modern-day seismic recordings converted to a Wood-Anderson seismogram to investigate these detectability limits. By combining the two approaches, we conclude that for M≥4, the earthquake catalog is complete since 1932 in California and most of Nevada.

Presenting Author: Yuehua Zeng

Authors