A powerful earthquake registered by the JMA as M7.2 hit near the east coast of Honshu, Japan at 09:09 UTC (18:09 JST) on March 20, 2021. The agency is reporting a depth of 60 km (37 miles). USGS is reporting M7.0 at a depth of 54 km (33 miles). JMA has issued tsunami advisories and forecasts for the nearby coast.
The epicenter was located 27.5 km (17.1 miles) WNW of Ishinomaki (population 117 233) and 34 km (21 miles) E of Yamoto (population 32 028), Japan.
There are about 2 630 000 people living within 100 km (62 miles) of the epicenter.
1 029 000 people are estimated to have felt strong shaking and 2 340 000 moderate.
Image credit: TW/SAM, Google
JMA has issued a Tsunami Advisory and Forecast for the nearby coasts. Waves up to 1 m (3.3 feet) high are expected.
Image credit: JMA
Image credit: JMA
Based on the preliminary earthquake parameters, hazardous tsunami waves are possible for coasts located within 300 km (186 miles) of the earthquake epicenter, PTWC said.
A tsunami is a series of waves. The time between wave crests can vary from 5 minutes to an hour. The hazard may persist for many hours or longer after the initial wave.
Impacts can vary significantly from one section of coast to the next due to local bathymetry and the shape and elevation of the shoreline. Impacts can also vary depending upon the state of the tide at the time of the maximum tsunami waves. Persons caught in the water of a tsunami may drown, be crushed by debris in the water or be swept out to sea.
The USGS issued a Green alert for shaking-related fatalities and economic losses. There is a low likelihood of casualties and damage.
Overall, the population in this region resides in structures that are resistant to earthquake shaking, though vulnerable structures exist. The predominant vulnerable building types are heavy wood frames and reinforced/confined masonry construction.
Recent earthquakes in this area have caused secondary hazards such as tsunamis, landslides, and fires that might have contributed to losses.
Estimated population exposure to earthquake shaking
Selected cities exposed
Featured image credit: TW/SAM, Google