Analysis of Myanmar Earthquake by Japanese Seismic Scientists

Seismic scientists Tsutsumi and Yagi analyze a 7.7 magnitude quake near Mandalay, Myanmar, caused by movement on the Sagaing Fault. They highlight the fault’s history of significant quakes and the need for vigilance against aftershocks. They also discuss the speed of earthquake rupture and implications for damage in bordering countries like Thailand.

Two Japanese seismic scientists have analyzed the recent significant earthquake near Mandalay, Myanmar. Professor Tsutsumi Hiroyuki from Doshisha University stated that the quake was caused by movement along a 200-kilometer stretch of the Sagaing Fault, which originated from the Indo-Australian plate’s interaction with the Himalayas. The fault spans approximately 1,500 kilometers, making it a major geological feature known for past magnitude 7 earthquakes since the 1800s. Tsutsumi indicated that such large quakes typically occur every 100 to 200 years on different sections. Historical data shows the last major quake occurred in 1839.

Preliminary reports categorize last Friday’s quake with a magnitude of 7.7 as the strongest on the Sagaing Fault in recorded history. Tsutsumi advised ongoing vigilance for aftershocks and potential additional quakes resulting from this seismic event. Meanwhile, Professor Yagi Yuji from the University of Tsukuba researched the seismic waves to understand rupture mechanics. He explained that the rupture initiated from the epicenter, spreading south initially for about 10 seconds, before moving both north and south, completing a total rupture duration of approximately 70 seconds.

Yagi noted that the rupture propagation speed may have matched or exceeded that of the seismic wave velocity, leading to heightened destruction. He speculated that neighboring Thailand, in the direction of the fault rupture, likely experienced significant damage due to the quake’s intensity. He cautioned that fast-moving fault ruptures can generate potent seismic waves, emphasizing the unruptured southern sections of the fault where strain could accumulate, signifying a potential risk for future seismic activity.

The article provides insights from Japanese seismic experts on the recent 7.7 magnitude earthquake in Myanmar. Professors Tsutsumi and Yagi outlined the geological characteristics of the Sagaing Fault and the earthquake’s destructive potential. Their analyses underline the importance of monitoring aftershocks and emphasize ongoing seismic risks due to unruptured fault sections.Additionally, damage assessments in neighboring regions, particularly Thailand, require further investigation due to their proximity to the fault line.

Original Source: www3.nhk.or.jp