A magnitude 5.3 earthquake, measuring a lower 5 on Japan’s seismic intensity scale, struck western Kanagawa Prefecture at 7:57 p.m. on Friday.
There was no threat of a tsunami, and there were no immediate reports of injuries or damage.
Lower 5 intensity shaking was felt in the city of Atsugi, the towns of Nakai and Matsuda, and the village of Kiyokawa in Kanagawa. The quake, which occurred at a depth of 13 kilometers, was felt across a wide area, including in Tokyo.
Friday’s jolt, which prompted some emergency early warnings to be sent to mobile phones, came a day after a magnitude 7.1 quake shook the Kyushu region and prompted the weather agency to issue its first ever alert that a megaquake in the Nankai Trough is slightly more likely than usual. The epicenter of Friday’s quake is outside of the area covered by that alert.
Shinichi Sakai, of the University of Tokyo's Earthquake Research Institute, told NHK that the anticipated Nankai Trough earthquake occurs at the plate boundary, differing in mechanism from Friday evening’s quake, which likely originated within the Earth's crust.
“The possibility that such earthquakes could be precursors to larger ones cannot be ruled out, so continued caution regarding future seismic activity is necessary," said Sakai, an expert on seismic activity in the Kanto region.
The central government set up an information liaison office for Friday’s quake at the crisis management center of the Prime Minister’s Office.
Speaking after the quake, Prime Minister Fumio Kishida said he had not received any information about damage, and urged the public react calmly to the Nankai Trough alert.
The emergency information "does not urge precautionary evacuations nor does it warn in detail that an earthquake will occur within a specific timeframe," he said. "I call on people to reconfirm their earthquake preparations while continuing their everyday social and economic activities, including traveling."
After the quake, the Tokaido Shinkansen line was suspended between Tokyo and Hamamatsu stations, but the line fully reopened shortly after 9 p.m.
The Tokaido Line was also suspended between Odawara and Atami stations, with delays impacting a wider area. The operator said it was unclear when the section would be reopened.
The Odakyu Line was suspended between Ebina and Odawara stations. The operator said staff were conducting inspections on foot, and that a return to normal service could take a "considerable amount of time." The company said it was providing alternate transportation via other lines.