Based on their depth, the expert and analysis staff of the Regional Earthquake Center (PGR) I Endah Puspita Sari said here on Sunday that 107 of the earthquakes were shallow earthquakes and eight were intermediate earthquakes.
"Most of the earthquakes, or 103 earthquakes, occurred on land, while 12 others occurred at sea. Nearly 112 of the earthquakes that occurred in the second week had a magnitude of below 4, while the rest had a magnitude of 4," she said.
Meanwhile, a researcher at the Regional Earthquake Center (PGR) 1 Marzuki Sinambela said only two of the 115 earthquakes were felt by the people, including those in Sinabang-Aceh at level II-III MMI on May 10, 2021, at 20:44:33 UTC or on May 11 at 03:44:33 local time, and in Samosir-North Sumatra at level III MMI on May 11, 2021, at 07:15:30 local time.
No casualty or material damage was reported in the quakes.
Based on earthquake sources, most of the earthquakes, or 71 earthquakes in the second week of May 2021 were caused by seismic activity around Samosir. Meanwhile, in the subduction area, there were 15 earthquakes, followed by other faults in a smaller number.
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