Moderate Earthquake Shakes Tokyo
Map of earthquake location today (Feb. 19, 2013) in Tokyo, Japan.
Credit: USGS.

An offshore earthquake of preliminary magnitude 5.6 shook Tokyo today, according to the U.S. Geological Survey (USGS).

The temblor's epicenter was 32 miles (52 km) east of Ohara, Japan, and 77 miles (124 km) east-southeast of Tokyo. It originated 21.7 miles (35 km) deep and struck at 9:27 p.m. local time (1227 UTC), the USGS reports.

There was light to moderate shaking around Tokyo and nearby Chiba, according to the USGS, but no immediate reports of damage.

Earthquakes of this size may cause minor to moderate damage, such as cracked plaster, but the damage caused by any single event depends on the quake's depth, proximity to populated areas, building standards in the region, as well as the type of earthquake. The USGS frequently updates the magnitude of an event after more data is analyzed.

An earthquake's magnitude is a measure of the energy released at the source. It is just one predictor of the shaking that may ensue, which is affected by local and regional geology. Scientists know in a general sense what causes Earthquakes but are unable to predict specific quakes.

This article will be updated if significant additional information becomes available. Find more earthquake news here.