A seismologist in Japan said the earthquake that shook greater Tokyo on Thursday night was similar to the 2005 temblor that struck the northwestern part of Chiba Prefecture.
Professor Furumura Takashi of the University of Tokyo's Earthquake Research Institute said Thursday's quake resembled the one in 2005 in its intensity and the location of its focus.
Thursday's quake had a magnitude of 5.9. The focus of the quake was in Chiba Prefecture east of Tokyo, at a depth of 75 kilometers. It jolted parts of Tokyo and Saitama with an intensity of five-plus on the Japanese scale of zero to seven.
The 2005 quake had a magnitude of 6.0, shaking Tokyo's Adachi Ward with an intensity of five-plus.
Furumura said the focus of the Thursday quake was situated in a seismically active area.
He said the depth of the focus and the mechanism of the quake suggest that it may have occurred inside the Pacific Plate, or on the border between the plate and the Philippine Sea Plate.