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Seismo-Acoustic Signatures of Proximal Earthquakes From the Stanley, ID, USA Aftershock Sequence in 2020

Session: Infrasound and the Seismo-Acoustic Wavefield III

Type: Oral

Date: 4/22/2021

Presentation Time: 10:30 AM Pacific

Description: 

Earthquakes as small as M2 produce infrasound that is detectable by infrasound arrays at proximal distances of several tens of kilometers. We report on observations from several hundred proximal earthquakes (M2.5-M4.0) recorded using seven infrasound mini-arrays (3 sensors) and broadband seismic data located less than 25 km from earthquake epicenters in the Stanley (Idaho) earthquake aftershock sequence. Analysis of many events permits comparison of earthquake source parameters and infrasound generation including relationships between source size, source depth, focal mechanism, and seismo-acoustic energy partitioning (i.e., energy radiated into the atmosphere compared to the ground).

A previous study focused on a single MWR3.6 from 7 April 2020 and used array back azimuth and back projection constraints to locate regions of infrasound generation. It found that the recorded infrasound wavefield is composed of both primary infrasound generation (at or near the infrasound arrays) and secondary radiators located throughout the region, which appear to be concentrated in areas of high topographic relief. Similar analysis is presented here for several hundred events and will permit the construction of ‘heat’ maps delineating areas of particularly pronounced infrasound generation.

Presenting Author: Jeffrey B. Johnson

Student Presenter: No

Authors