WITHDRAWN Earthquake Detection Using a Submarine DAS Array in Monterey Bay, California
Description:
W/DThe Seafloor Fiber-Optic Array in Monterey Bay (SEAFOAM) is a year-long Distributed Acoustic Sensing (DAS) deployment project, with a goal of local seismicity monitoring. An interrogator (model QuantX, OptaSense) was connected to a 52-km long submarine cable, turning it into a DAS array of 10245 channels with 5-meter channel spacing. Recording started on July 21, 2022. The region is seismically active because of the nearby San Andreas fault system, and offshore San Gregorio fault system which the cable crosses. The 1989 M6.9 Loma Prieta earthquake occurred just north of Monterey Bay, and a magnitude 7+ earthquake is believed to happen on the San Gregorio fault after 1270 AD. Applying DAS to submarine cables can benefit systems like Earthquake Early Warning (EEW) by increasing warning time and improving accuracy for offshore events.
F-K domain filters have been applied to denoise the raw data. P- and S-wave phase picking results with STA/LTA methods show different performance with different background noise (channel water depth, substrate composition, stormy weather etc.), which implies that dynamic parameter selection is needed. The dense spatial sampling nature of a DAS array is used to filter out bad picks and obtain more robust results. A 1D velocity model is used to locate earthquakes with P-wave arrivals. Location results only using the DAS array show expected strong trade-off between earthquake epicenter and origin time, for events outside of the array. On-land stations are added to better constrain the locations. Estimation of magnitude for local earthquakes using peak strain-rate data after 3s of the P-wave arrival shows promising results when using catalog locations. Spatially down-sampled data is streamed in real time to the Northern California Earthquake Data Center (NCEDC). These data are processed together with data from on-land seismic stations using a version of the rapid earthquake source parameter estimation EEW algorithm EPIC. DAS data currently contributes to event location in a very similar way as seismic data does, demonstrating the possibility to increase warning time for offshore events.
Session: Understanding Earth Systems with Fiber-optic Cables [Poster]
Type: Poster
Date: 4/19/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Yuancong Gou
Student Presenter: Yes
Invited Presentation:
Authors
Yuancong Gou Presenting Author Corresponding Author yuancong_gou@berkeley.edu University of California, Berkeley |
Richard Allen rallen@berkeley.edu University of California, Berkeley |
Li-Wei Chen liwei_chen@berkeley.edu University of California, Berkeley |
Taka'aki Taira taira@berkeley.edu University of California, Berkeley |
Ivan Henson ihenson@berkeley.edu University of California, Berkeley |
Julien Marty jmarty@berkeley.edu University of California, Berkeley |
Douglas Neuhauser dougneuhauser@berkeley.edu University of California, Berkeley |
Brian Pardini bpardini@berkeley.edu University of California, Berkeley |
Stephen Thompson stephen.thompson@berkeley.edu University of California, Berkeley |
Victor Yartsev Victor.Yartsev@optasense.com OptaSense, Chino, California, United States |
Junli Zhang junlizhang@berkeley.edu University of California, Berkeley, Berkeley, California, United States |
Stephane Zuzlewski stephane@berkeley.edu University of California, Berkeley, Berkeley, California, United States |
Barbara A Romanowicz barbarar@berkeley.edu University of California, Berkeley, Berkeley, California, United States |
WITHDRAWN Earthquake Detection Using a Submarine DAS Array in Monterey Bay, California
Category
Understanding Earth Systems with Fiber-optic Cables