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An Analysis of Air-to-Ground Coupled Seismic Arrivals From the Camp Minden, U.S., Explosion, 16 October 2012

Session: Infrasound and the Seismo-Acoustic Wavefield [Poster]

Type: Poster

Date: 4/20/2021

Presentation Time: 04:15 PM Pacific

Description: 

Co-located microbarometers and seismometers in the spatially dense USArray Transportable Array (TA) provide a unique opportunity to study air-to-ground coupled signals (Vergoz et al., 2019). Infrasound signals, resulting from an accidental explosion which occurred 2012, October 16^th ~04:25 UTC, at Camp Minden Army Ammunition Plant, Louisiana, USA, were recorded up to 1482 km away in southern Florida, aided by a dominant stratospheric duct, enhancing propagation to the east, consistent with existing atmospheric specifications. Air-to-ground coupled seismic signals were recorded on co-located seismometers up to 1049 km east of the event. Air-to-ground coupling coefficients were calculated using maximum trough-to-peak amplitudes at each station that recorded both infrasound and seismic signals. These coefficients range from 3.96E-05 to 9.76E-08 ms^-1/Pa consistent with previous studies (Albert et al., 2013; Edwards et al., 2008). Despite significant scatter, calculated coefficients from soft rock sites in the Mississippi embayment exhibit coupling coefficients approximately an order-of-magnitude larger than those from hard rock sites in the Appalachian mountains. The high spatial density of recordings provides a clear observation of rapid lateral change from the ensonified region to the shadow zone, consistent with simulations of the stratospheric propagation using an in-house atmospheric acoustic modal modelling code.

UK Ministry of Defence ©Crown Owned Copyright 2021/AWE

Presenting Author: Gemma Wills

Student Presenter: No

Authors