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Investigating Tremor-like Episodes at Salt Domes Used for Underground Energy Storage in the US Gulf Coast

Description: 

Underground storage caverns in salt domes have become increasingly critical in the energy transition, particularly for storing fuels such as hydrogen. The recent loss of structural and mechanical integrity at caverns in the Sulphur Mines salt dome and the potential threat to the Chicot Aquifer highlight an even greater need for monitoring hazards for environmental protection and the public safety of local communities. Monitoring and identifying structural instabilities and hazards at storage sites present significant challenges due to the small event magnitudes, waveform complexities, and the sparsity of observations. Microearthquakes offer important insights into the mechanical behavior of salt boundary shear zones. In addition, a previous study found that tremor-like episodes preceding the cavern collapse and sinkhole formation at the Napoleonville salt dome were associated with greater seismic energy release. These episodes were followed by quiet periods during which strain was built back up for new seismic events. The characteristics of such episodes could signal the weakening of the mechanism driving the seismicity. To better understand the characteristics of seismic signals at underground storage sites, we analyzed tremor-like signals recorded at two locations in Louisiana: the Sorrento salt dome near Sorrento and the Napoleonville salt dome near Bayou Corne. Previous research at Bayou Corne identified two large tremor-like episodes followed by 3+ hours of quiescence periods. Using data from 31 July to 6 August 2012 recorded at six broadband stations, we manually identified three additional episodes that occur for at least 2.5 minutes on 31 July 2012 and display at least eight microseismic events within a single episode. Tremor-like episodes are observed at all stations, however, they are difficult to identify as one might mistake them for noisy signals. We also present teleseismic data from the US Array station 545A showing that distant earthquakes from Mexico and Peru were recorded near Bayou Corne but are not tremor-triggering events.

Session: New Directions in Environmental, Seismic Hazard and Mineral Resource Exploration Studies [Poster]

Type: Poster

Date: 4/17/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Katleho

Student Presenter: Yes

Invited Presentation: 

Poster Number: 117

Authors