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The Monte Cristo Range Mw 6.5 Nodal Geophone Rapid Deployment

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

Type: Poster

Date: 4/20/2021

Presentation Time: 11:30 AM Pacific

Description: 

The Nevada National Security Site deployed 48 nodal geophones within 34 hours of the Monte Cristo Range (MCR) Mw 6.5 earthquake that occurred at 11:13 UTC May 15, 2020. The first geophone was planted within 16 hours of the main shock and a series of four deployments were conducted to maintain near continuous recording from May 15 – August 19, 2020. The systems were deployed along roads, with the main line trending east-west for 15 km and a north-south line running 3 km along Highway 95 with approximately 500 m station spacing. The east-west line parallels a significant section of the ENE striking sinistral mainshock rupture. The systems recorded at 500 sps with orientation of the inline channel to the North and leveled vertically. Each deployment had fewer than two systems fail and collected a half terabyte of data, for a total of two terabytes of data over three months. Much of the energetic aftershock period was recorded on the dedicated nodal array near the main fault offsets of the MCR earthquakes. The main shock and subsequent large events were recorded by an additional nodal array that was already deployed at the Nevada National Security Site (NNSS) at ~200 km epicentral distance. These complementary data sets provide a unique opportunity to demonstrate the use of geophones for deployment and the recording of significant events. The initial review of data shows that for every initial cataloged event there are likely a dozen additional events that can be visually identified on the geophone data. We are developing a micro seismic localization algorithm that detects additional events in the subsurface that do not correspond to published events. We will continue to refine event locations and develop an improved velocity model for the event region.

Presenting Author: Cleat Zeiler

Student Presenter: No

Authors