Sun, 31 Jan 2021, 22:56 22:56 PM | BY: EARTHQUAKEMONITOR
4.2 quake 31 Jan 4:36 pm (GMT -6)
A magnitude 4.2 earthquake near Puntarenas, Provincia de Puntarenas, Costa Rica, was reported only 12 minutes ago by the Nicaraguan Institute of Territorial Studies (INETER), considered the main national agency that monitors seismic activity in this part of the world. The earthquake occurred at a shallow depth of 10 km beneath the epicenter in the afternoon on Sunday 31 January 2021 at 4:36 pm local time. The exact magnitude, epicenter, and depth of the quake might be revised within the next few hours or minutes as seismologists review data and refine their calculations, or as other agencies issue their report.
Detailed earthquake information - overview map, magnitude, time, depth, source, shake map, list of reports. File an "I felt it" report if you felt the quake! Features interactive map, read user reports and get links to further info.
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29 Jan 11:26 UTC: First to report: EMSC after 3 minutes.
29 Jan 11:32: Magnitude recalculated from 5.0 to 4.8. Epicenter location corrected by 4.9 km (3.1 mi) towards WNW.
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29 Jan 11:33: Magnitude recalculated from 4.8 to 5.0. Hypocenter depth recalculated from 10.0 to 20.0 km (from 6.2 to 12.4 mi). Epicenter location corrected by 5.7 km (3.5 mi) towards N.
29 Jan 11:48: Magnitude recalculated from 5.0 to 4.9. Hypocenter depth recalculated from 20.0 to 30.0 km (from 12.4 to 18.6 mi). Epicenter location corrected by 1.6 km (1 mi) towards NW.
29 Jan 13:23: Epicenter location corrected by 2.2 km (1.4 mi) towards S.
29 Jan 13:50: Hypocenter depth recalculated from 30.0 to 10.0 km (from 18.6 to 6.2 mi). Epicenter location corrected by 3.5 km (2.2 mi) towards WSW.
Update Fri, 29 Jan 2021, 11:30
Significant magnitude 5.0 earthquake 57 km southwest of David, Panama
More info
Based on its magnitude, the fault that was active during the quake ruptured along a surface of approx. 40 km
2 (=15 sqare miles) as a first-order estimate. The length of the rupture zone thus was probably around 11 km (7 mi).
Aftershocks typically occur during the days and weeks following the quake at or near the same fault, at distances of up to approx. two times the length of the rupture zone.
The often broadly linear arrangement of aftershock epicenters encompasses the rupture zone of the main shock (check on the map below to verify).
Recorded aftershocks, latest first (59 quakes):
18 Mar 2021 17:18 UTC | M 3.6 |