Delta CFF in the shallow area at a depth of 3.5km due to earthquakes of July 1 and 9 in the sea near the Kozushima Island and an earthquake in the sea near the Niijima Island on July 15
Many shallow earthquakes have occurred from the night of July 19
to July 20. Many shallow earthquakes from the night of July
19 to July 20 motivates us to recompute the induced stress pattern
at a depth of 3.5km. At a depth of 3.5km, regions with increasing stress change are distinctively stretching from north to south
between the west sea area to the To-shiri and the east sea area to the
Shikinejima and the Kozushima Islands.
Many earthquakes on the morning of July 20 occurred in the regions with
increased stress change around the Kozushima and Shikinejima Islands.
Hypocenter plot: manually determined at Tokyo University ERI Earthquake
Observation center
Fault parameter: Refer to EIC Seismological note, 2000 by Dr. Kikuchi and
Yamanaka