[3] Although its epicentre lay just offshore near Chōshi city, the shallow magnitude 6.1 Mj earthquake produced considerable shaking inland through much of the Bōsō Peninsula and lower Ibaraki Prefecture.

It occurred as a result of normal faulting in a seismically quiet region, possibly in response to the magnitude 9.0 Mw 2011 Tōhoku earthquake.

[5][6] A seismically volatile country, Japan frequently experiences natural disasters such as earthquakes, volcanic eruptions and tsunamis.

[8] The largest of the islands, Honshu is characterised by numerous inland fault systems and large subduction zones which are a result of the interaction between several tectonic plates.

[9] At the junction of the continental Okhotsk microplate and the oceanic Philippine Sea and Pacific plates lies the populous Kantō Region, which has had a long history of devastating earthquakes.