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Surface Rupture and Slip Distribution of the 2025 M7.7 Mandalay, Burma (Myanmar) Earthquake

Description: 

The March 28, 2025, M7.7 Mandalay, Burma (Myanmar), earthquake produced one of the longest surface ruptures observed globally. The rupture occurred on the dextral Sagaing fault through central Myanmar, causing destruction and devastation in Myanmar and Thailand. The Sagaing fault has a history of M>7 earthquakes in the last 100 years, and the 2025 earthquake occurred in a region that had not hosted an M>7 earthquakes since 1839. Earthquake scientists at the U.S. Geological Survey (USGS) have been compiling surface rupture observations and making them available via an online webmap for rapid use by scientists and emergency responders. Here we describe the observations as of April 8, 2025. Sub-pixel correlation of Sentinel-2 (S2, 10 m/pixel) optical images acquired before and after the earthquake reveals a ~475-km- long surface rupture with a simple, linear, discrete fault trace. The extreme length and simplicity of the fault trace are confirmed with sub-pixel correlation of Planet Dove (3 m/pixel) optical images from before and after the earthquake. Displacement profiles from the S2 pixel correlation result in a peak surface slip of ~5.5 (+1.3/-2.1 m) approximately 15 km north of the epicenter with an average slip of ~3.6 ± 1.15 m for the entire rupture. Detailed surface rupture mapping on high-resolution (<= 0.5 m/pixel) optical images from WorldView 1, 2, and 3 (© 2025 Maxar), and SkySat (© 2025 Planet UBC) reveals largely continuous rupture within a narrow fault zone (≤25m) that follows the long-term geomorphic expression of the Sagaing fault. As of April 8, we reviewed 53% of the rupture covered by high-resolution imagery and mapped detailed surface rupture. Manual mapping of displaced features (e.g., roads and field edges) visible in high-resolution optical images thus far yields 51 high-confidence measurements, with a peak of 4.7 (-1.0/+1.3) m and an average slip of 3.2 ± 0.9 m. Manual measurements tend to be smaller than the S2 displacements and mostly overlap within uncertainty. We will continue updating the USGS webmap (https://doi.org/10.5066/P1RYMWCK) as more data become available.

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: Nadine

Student Presenter: No

Invited Presentation: 

Poster Number: 155

Authors