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Machine Learning Aftershock Detection for the m6.5 31 March 2020 Stanley, Idaho Earthquake

Session: Intermountain West Earthquakes in the Spring of 2020 [Poster]

Type: Poster

Date: 4/20/2021

Presentation Time: 11:30 AM Pacific

Description: 

The March 31, 2020, Mw6.5 Stanley, Idaho, earthquake was recorded by a sparse regional network of permanent seismic stations. Succeeding the mainshock, a local network of 15 seismic stations within and surrounding the epicentral zone was installed. The real-time part of the new network (2 stations) enabled local P and S wave phase picking and has helped to produce a robust event catalog. Since installing the temporary network after the mainshock in March, 2590 events have been detected (USGS catalog) with an initial completion magnitude of M2.4. Aftershocks provide critical insights in determining the where and potentially why the slip occurred. In addition, aftershock models and the spatial distribution of such events are of great importance when forecasting future seismicity. Thus moving forward, as aftershocks are detected on the still deployed temporary network, we will be able to lower the completion magnitude and further revise the local velocity model. To further reduce the completion magnitude of this sequence with the existing data, we began building a revised catalogue of small magnitude aftershocks by picking the arrival times of P and S waves across the temporary network and relocating existing events using HypoDD and a local velocity model we compiled from previous Vp and Vs imaging studies in the region. To detect lower magnitude events (<M2.4) we employ deep learning. This method solves common problems associated with detecting low magnitude seismic events that have a low signal-to-noise ratio. Overall we conclude that machine learning will assist in small event identification, alongside STA/LTA detection and hypocenter relocation; therefore enabling us to determine with greater certainty the driving mechanisms of the M6.5 Stanley Earthquake.

Presenting Author: Spencer F. Wilbur

Student Presenter: Yes

Authors