Researcher of the Regional Center for Earthquake 1 at Medan's Meteorological, Climatological, and Geophysical Agency (BMKG), Marzuki Sinambela, expounded here on Monday that the earthquakes were of two types, a medium-depth type caused by subduction and a shallow-depth quake associated with local faults and caused by fluid intrusion into the seismogenic zone of local fault activity.
The highest magnitude of the earthquakes that struck during the period from January to April 19, 2021, was recorded at 3.9. Meanwhile, the mean earthquake depth when magnitude M was recorded below 2.4 was found to be less than 5 km.
According to the BMKG, further study should be conducted on the earthquakes in Samosir since the largest had occurred in the districts of Palipi, Nainggolan, and Onan Runggu.
In addition, the agency deemed it necessary to conduct a follow-up to unearth details of tectonic conditions in Samosir .
The BBMKG Region I has appealed to the public to avoid succumbing to undue panic over the earthquake and to contact Medan's BMKG for correct information.
In the meantime, Reza, the analysis staff of the Regional Earthquake Center (PGR) I, pointed to 12 earthquake events in Samosir on April 18, 2021, with magnitudes of 1.6-3.9.
The PGR I records drew a link between the quake that struck Samosir and the ones that struck in the previous months on the basis of the epicenter distribution.
The earthquake distribution is quite large, though no mainshock earthquake, with a significant magnitude, was recorded. Related news: Indonesia's Aceh Besar District hit by 5.5-magnitude quake
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