A very strong Magnitude 7.5 earthquake has prompted a temporary tsunami watch for parts of the pacific, The quake was detected by the United States Geological Survey about 450 kilometers south of Petropavlovsk-Kamchatskyi, the capital of the Russian region Kamtchatka. Shaking was felt across the region and on most of the Kurile Islands as far south as Japan. However, the closest distance between epicenter and land was about 200 kilometers. Thus, no major damage was expected due to the weak shaking.
The initial tsunami watch for parts of the northwestern Pacific was lifted soon. The quake occurred in a depth of 56 kilometer not rupturing to the surface and so was unlikely to cause a noteworthy tsunami. However, the origin mechanism of this quake was rather uncommon, as it ruptured a blind thrust fault (same faulting-style as a subduction zone) the lower-most part of the (actual elastic) oceanic lithosphere (Pacific Plate) right in front of the Kuriles subduction arc.
The subduction fault itself, which is capable of producing Magnitude 8.5+ quakes, was not affected by the rupture.
Only a few aftershocks have been detected since the mainshock, the strongest reaching magnitude 4.7. However, stronger aftershocks around magnitude 6 cannot be excluded for the next couple of weeks, although none of them would pose any threat to settlements.
With magnitude 7.5 this quake marks the second-strongest quake of the year 2020 so far. 10 to 15 quakes larger than magnitude 7 happen around the world every year, so the size of this quake is not unusual at all.
|02/13/2020 10:33 a.m.||Earthquake offshore Kuril Islands, Russia||Mw 7|