Speaker
Description
The Korean Peninsula is located in the far-eastern
Eurasia plate, and belongs to intraplate seismicity
regime with low seismicity. The instrumental seismicity
is scattered over the peninsula, with relatively high
seismicity at paleo-tectonic regions that are associated
with paleo-rifting and paleo-collision. The paleo-rifting
is responsible for the separation of Japanese islands
from the Eurasian plate. The paleo-continental collisions
formed a current shape of Korean Peninsula. It is known
that dozens of devastating earthquakes with magnitudes of
7 occurred historically. The paleo-structures appear to
be reactivated by the current ambient stress field. The
Korean Peninsula is located at about 1200 km away from
the 11 March 2011 M9.0 Tohoku-Oki earthquake. Nine
triggered earthquakes within one hour after the
Tohoku-Oki earthquake were identified in the Korean
Peninsula. The sizes of triggered earthquakes are small,
allowing observation only at stations in nearby
distances. The short PS differential times suggests that
the earthquakes appear to occur by brittle failure in
shallow crust. The focal mechanism solution of the
largest triggered earthquake presents normal-faulting
sense of motion with a tensional axis in the southeast,
suggesting that the event occurred due to the response to
the displacement caused by the Tohoku-Oki earthquake. We
present the spatio-temporal evolution of the Korean
seismicity before and after the Tohoku-Oki earthquake.
The response of intraplate regime to the rapidly sweeping
dynamic stress field is discussed.
