← Back to Sessions

Detection of Seismic Events Near the Southern Anninghe Fault Using a Local Dense Array

Description: 

The Anninghe fault (ANHF) is one of the major faults on the southeastern margin of the Tibetan Plateau and has produced a few large earthquakes in history (e.g., the 1536 Xichang M7.5 earthquake). Seismic quiescence for M4 events in the recent 40 years and high interseismic locking degree near the southern segment of ANHF emphasize the high seismic hazard of this region.

To better assess the recent fault behavior of ANHF, we used a dense temporary seismic array consisting of 132 three-component instruments to detect local seismic events near its southern segment. After detection with a machine-learning phase detector (EQTransformer), phase association (REAL), and absolute location (Hypoinverse), we obtained an initial catalog with more than 400 events. The matched filter detection method was also applied to array waveform data to detect potential hidden events. Finally, our relocation results reveal five clusters of events around the array, and after both waveform characteristic and spatiotemporal distribution analyses, four of which are probably attributed to mining blasts while the remaining one consists mainly of natural earthquakes that occurred northwest of the main fault. We detected a small number of on-fault earthquakes down to 15 km beneath our array, which is further compared with the existing catalogs and the previously inverted interseismic locking models. We suggest that there might exist some smaller but currently more active faults around the highly locked southern Anninghe fault, and dense array recordings could help increase both the completeness and accuracy of the seismic catalog over our study region.

Session: Tectonics and Seismicity of Stable Continental Interiors [Poster]

Type: Poster

Date: 4/19/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Junhao Song

Student Presenter: Yes

Invited Presentation: 

Authors