Re-Analysis of Pre-Digital Earthquakes in the Mendocino Triple Junction Region

Session: Back to the Future: Innovative New Research with Legacy Seismic Data [Poster]
Type: Poster
Date: 4/28/2020
Time: 08:00 AM
Room: Ballroom
Description: 

The high seismicity of the Mendocino Triple Junction region (over 35 events of M>6 in the past 100 years) reflects the complex interaction of the San Andreas fault, Mendocino fracture zone and southern Cascadia subduction zone as well as internal deformation of the Gorda plate. I am using a combination of relocation techniques and waveform comparisons of pre-digital earthquakes to digital era events to better understand the moment release, slip partitioning and coupling between fault systems of this region. Preliminary relocations of M > 5 earthquakes occurring in the region indicate that most events between 1915 and 1940 were located within the southern Gorda plate and along Mendocino fracture zone. Although this same region remained active between 1940 and 1960, there appears to be an increase in seismicity within the central Gorda plate during this 20 year period. Initial comparisons of regional waveforms for a sequence of M>6.3 events occurring near the Mendocino fracture zone between February and October 1941 suggest strike-slip faulting along faults with differing orientations.

Presenting Author: Diane I. Doser

Authors