ABOUT
The seismic response at the MiDAS site to the 2 April 2024 Mw 7.4 Hualien, Taiwan earthquake was comprehensively recorded by the distributed acoustic sensing (DAS) system, which has been operational since 2022.
DAS Configuration
The DAS installation along the Milun fault employs optical fiber sensors that measure strain rate over a 10 m gauge length, sampled at 4 m intervals along the entire fiber. The system spans approximately 6.7 km, yielding 1,666 channels at a sampling frequency of 1,000 Hz.
MiDAS Data Format
To facilitate further seismological investigations using this unique dataset, we have established an online repository that provides DAS recordings in daily MiniSEED format. The archive covers the period from one week prior to the mainshock through 30 days afterward (27 March-3 May 2024). All traces were downsampled from 1,000 Hz to 100 Hz following the application of a 40 Hz low-pass filter. Despite compression, each daily MiniSEED tarball remains sizable, with a file volume of approximately 13 GB. In addition, the repository includes the fiber route map, borehole coordinates, and associated metadata.
Experimental DAS Repository
This data release serves as a valuable test case for understanding how to share a comprehensive DAS dataset with the broader community. It is now publicly accessible worldwide through the link at https://midas2024.earth.sinica.edu.tw
