M4.9 quake hits off Ibaraki coast, part of active sequence near Japan Trench

A magnitude 4.9 earthquake struck off the Pacific coast of eastern Japan on November 10, 2026, at 05:20 UTC — 2:20 p.m. local time — centered about 78 kilometers east-southeast of Hitachi in Ibaraki Prefecture, at a depth of roughly 30 kilometers. No tsunami warning was issued, and no casualties or damage have been reported.

The European-Mediterranean Seismological Centre placed the epicenter at 36.25°N, 141.57°E and recorded a depth of 30 km. The event was also logged with coordinates of approximately 36.33°N, 141.47°E.

The quake is the latest in a cluster of seismic events that began the previous day. On November 9, a magnitude 5.9 earthquake — measured by the Japan Meteorological Agency — struck off the Ibaraki coast at 1:52 p.m. local time at a depth of about 10 kilometers, producing a maximum seismic intensity of 3 across parts of Miyagi, Fukushima, Ibaraki, and Tochigi prefectures, with tremors felt as far as Tokyo's Arakawa and Adachi wards. The JMA said there was no tsunami risk from that event either.

The USGS measured that same November 9 event at magnitude 5.7, at a depth of 24.2 kilometers, and issued a green PAGER alert indicating a low likelihood of casualties or damage. The two agencies' differing figures reflect different measurement methods.

November 9 alone brought a rapid succession of tremors: a magnitude 3.5 quake in northern Ibaraki at 3:15 a.m., a magnitude 4.5 off Miyagi at 5:16 a.m., the main M5.9 shock at 1:52 p.m., and a magnitude 4.5 in the same region at 2:01 p.m. that was felt across Tokyo, Kanagawa, Fukushima, Miyagi, Niigata, and Nagano. A magnitude 6.1 earthquake had also struck the same waters on November 6.

The activity is occurring in a region that researchers are watching closely. A team from Tohoku University, the Japan Agency for Marine-Earth Science and Technology, and the University of Tokyo's Earthquake Research Institute has found that the plate boundary along the Japan Trench has re-locked since the 2011 Great East Japan Earthquake, with seafloor measurements indicating that compressive energy is once again accumulating.

The current state of the boundary represents a standard phase following a major event, and the study does not forecast an imminent earthquake.— Researchers cited by Jiji Press

The researchers used GNSS-A technology — combining satellite positioning with acoustic waves — to measure seafloor displacement at 26 locations. Megathrust earthquakes along the Japan Trench typically occur at intervals of 500 to 900 years, and the team emphasized that monitoring is essential for evaluating future earthquake and tsunami risks, but stopped short of predicting any near-term event.

Japan sits on the Pacific Ring of Fire, where several tectonic plates converge. The 2011 Great East Japan Earthquake resulted from a sudden slip along a long-locked section of the Japan Trench boundary. Both the JMA and the USGS continue to monitor ongoing activity in the region.

Why it matters — The ongoing seismic cluster off Ibaraki is unfolding in the same offshore zone where researchers have confirmed the Japan Trench plate boundary is re-locking and accumulating energy following the 2011 disaster — making continued monitoring directly relevant to earthquake and tsunami preparedness across eastern Japan.

Sources differ on Magnitude of the Nov. 9 main shock: 5.9 (gsmglobalnews.com (citing JMA)) vs 5.7 (gsmglobalnews.com (citing USGS))

Sources differ on Depth of the Nov. 9 main shock: 10 km (gsmglobalnews.com (citing JMA)) vs 24.2 km (gsmglobalnews.com (citing USGS))

Reported by usgs.gov, forecastbar.com, earthquaketrack.com, emsc-csem.org, volcanodiscovery.com, gsmglobalnews.com, arabnews.jp