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Strong-motion Data for the 28 March 2025 M7.7 Mandalay, Burma (Myanmar) Earthquake

Description: 

The 28 March 2025 M7.7 Mandalay, Burma (Myanmar) earthquake ruptured over 400 km of the Sagaing fault, the primary lateral plate boundary fault in the country. Nucleating near Mandalay, the rupture was primarily to the south, generating a swath of severe shaking that extended from Mandalay through the capital city of Nay Pyi Taw. The earthquake caused severe damage in Mandalay, Sagaing, Nay Pyi Taw, Bago, Shan State and other locations in proximity to the rupture, with damaging shaking extending over 100 km away from the fault. The Department of Meteorology and Hydrology (DMH) in Nay Pyi Taw operates the national seismic network (MM), which has been part of the International Federation of Digital Seismograph Networks (FDSN: doi:10.7914/SN/MM) since the network was upgraded in 2016 The DMH and its staff was severely impacted by the earthquake, the rupture of which was ~3 km from the network hub in Nay Pyi Taw. In spite of myriad challenges, the DMH provided authoritative information to their ministry and the local population about the earthquake and risk of aftershocks, and the mainshock was recorded by four stations in the country, at Yangon (MM.YGN), Keng Tung (MM.KTN), Nyaung-U (MM.NGU), and Nay Pyi Taw (GE.NPW). Strong motion data from these stations and one station in Chiang Mai, Thailand, (IU.CHTO) provided observational anchors for the USGS ShakeMap, and processed data are available from the Center for Engineering Strong Motion Data (https://cesmd.org). Vertical acceleration in excess of 1g was recorded at NPW, located ~3 km from the rupture trace, with horizontal peak ground accelerations (PGAs) of 0.63g, peak ground velocity (PGV) of 165 cm/s, and static offset of ~1.5 m. These extreme ground motions account for the severity of damage in Nay Pyi Taw and other locations close to the rupture. At Yangon, located in the southeastern corner of the Ayeyarwady Delta Basin, shaking was strongly felt, with PGA 2.4%g and PGV 10.2 cm/s, but not damaging per available reports (MMI 4-5). We describe available data and discuss preliminary results.

Session: Late-breaking on Recent and Future Large Earthquakes [Poster]

Type: Poster

Date: 4/15/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Susan

Student Presenter: No

Invited Presentation: 

Poster Number: 157

Authors