Japan: 4.9-magnitude earthquake strikes Tokyo January 6

Event

An earthquake with a magnitude of 4.9 on the Richter scale was felt in Tokyo at 00:54 (local time) on Saturday, January 6. The epicenter was located approximately 11 km (7 mi) outside Chiba. There were no immediate reports of casualties or damage and no tsunami warning was issued.

The quake came not long after an emergency earthquake warning was issued by the Japan Meteorological Agency earlier on Friday, January 5, stating that a 6.4-magnitude earthquake would hit Ibaraki in eastern Japan; authorities later said that the alert was a false alarm. The alert caused a minor panic and brief transportation disruptions in Tokyo. According to local sources, the alert was issued after an early warning system misread seismic data, and was not related to Saturday's 4.9-magnitude earthquake.

Context

Japan sits at the junction of four tectonic plates and experiences a number of relatively violent earthquakes every year. Rigid building codes and strict enforcement mean even strong tremors often do little damage. However, a massive undersea quake in March 2011 near Fukushima sent a tsunami barreling into Japan's northeastern coast, leaving more than 18,000 people dead or missing and sending three reactors into meltdown at the Fukushima nuclear plant. In April 2016, two strong earthquakes followed by more than 1700 aftershocks hit the southern prefecture of Kumamoto, leaving at least 50 dead and causing widespread damage.

Advice

Individuals present in the impacted region are advised to monitor the situation, to be prepared for aftershocks, and to adhere to any instructions issued by local authorities. In the event of aftershocks, individuals are advised to protect themselves as much as possible from falling debris if indoors (e.g. under a table), to move away from windows, and to not attempt to leave the building unless there is an immediate danger or on the ground flood. If outdoors, move away from tall buildings, utility wires, and streetlights.