[SIT30-01] Seismic recordings of ice collapses along Yarlung Tsangpo Grand Canyon
Keywords:ice collapses, Yarlung Tsangpo Grand Canyon, Seismic recordings
Mass-wasting events occur often in the Tibetan Plateau in response to the active tectonics and global warming. On October 16, 2018 a large landslide induced by ice collapses occurred in the Yarlung Tsangpo Grand Canyon at the Sedongpu Basin, blocked the Yarlung Zangbo River, and generated a flood with water levels rising 40 m above the original water level.
Here we present a study of the dynamic processes using broadband seismic waveforms recorded by seismic stations we deployed around the Yarlung Tsangpo Grand Canyon. These stations are located very close to the source area with good azimuthal coverage. Data show emergent onsets with a duration about 400 s and a clear late phase. The time history of the high-frequency spectrum is distinct from the time history of the low-frequency spectrum. The estimated moment is about 2.5*1015 Nm, which is equivalent to a moment magnitude of 4.2.
In the same way we identified several other later events at similar locations. These events have duration times of 250-400 s. The seismic analyses allowed us to recognize a new form of glacier instability in terms of their dynamic source process. It is likely that the plate tectonics, the monsoon rains and the glacier melts may all have contributed to the triggering mechanism of these kind of disasters.
Here we present a study of the dynamic processes using broadband seismic waveforms recorded by seismic stations we deployed around the Yarlung Tsangpo Grand Canyon. These stations are located very close to the source area with good azimuthal coverage. Data show emergent onsets with a duration about 400 s and a clear late phase. The time history of the high-frequency spectrum is distinct from the time history of the low-frequency spectrum. The estimated moment is about 2.5*1015 Nm, which is equivalent to a moment magnitude of 4.2.
In the same way we identified several other later events at similar locations. These events have duration times of 250-400 s. The seismic analyses allowed us to recognize a new form of glacier instability in terms of their dynamic source process. It is likely that the plate tectonics, the monsoon rains and the glacier melts may all have contributed to the triggering mechanism of these kind of disasters.