At least nine people are dead and 31 unaccounted for in Hokkaido after a magnitude 6.7 earthquake — reaching the maximum 7 on Japan’s seismic intensity scale in some areas — caused landslides that engulfed houses early on Thursday.
The quake centered east of the city of Tomakomai was felt strongly in Hokkaido’s capital of Sapporo, roughly 68 kilometers away. There was no tsunami risk.
A landslide along a long ridge in the rural town of Atsuma could be seen in aerial footage from NHK. The 3:08 a.m. quake also cut the power supply to nearly 3 million homes in the prefecture while grounding flights and disrupting train services.
Prime Minister Shinzo Abe put the death toll at nine while the Hokkaido Prefectural Government said about 300 people were injured in Sapporo and other cities.
The government said later in the day that about 340,000 homes had regained electricity.
The quake occurred at a depth of about 40 km and logged a 7 on the seismic intensity scale in Atsuma and a lower 6 in the city of Chitose, both southeast of Sapporo. The quake was initially reported to have registered a maximum intensity of upper 6.
A series of smaller shocks followed the initial quake, the agency said. At an early morning news conference, agency official Toshiyuki Matsumori warned residents to take precautions for potential major aftershocks in the coming days.
Prime Minister Shinzo Abe, arriving at his office before 6 a.m., told reporters his government had set up a command center to coordinate relief and rescue. His voice sounding haggard, Abe said saving lives was his government’s priority.
The Tomari Nuclear Power Station suffered a power outage but was cooling its fuel rods safely with emergency power, Chief Cabinet Secretary Yoshihide Suga said. External power at the station resumed by 1 p.m. Operator Hokkaido Electric Power Co. reported no radiation irregularities at the plant, which has been offline since shortly after the 2011 Great East Japan Earthquake, Suga told a news conference.
The power outage occurred when thermal power plants in the prefecture shut down automatically after the quake. The blackout also affected around 40 hospitals as well as telephone services and television broadcasting in the prefecture.
A fire broke out at a Mitsubishi Steel Mfg. Co. plant in the city of Nemuro but was later brought mostly under control, NHK said, quoting local officials.
There was also a fire at an oil refinery facility in Muroran, but it had almost been subdued by the afternoon.
New Chitose Airport was closed for the day after part of its terminal ceiling collapsed, as well as due to the power outage, the transport ministry said, affecting flights to and from Tokyo and other cities at the country’s fifth-busiest airport.
Bullet train and local train services were also disrupted by the quake, operators said.
In Tokyo, the central government said the Self-Defense Forces will dispatch 25,000 personnel for relief operations at the request of the governor of Hokkaido.
NHK footage showed a crumbled brick wall and broken glass at a home, and quoted local police as saying some people were trapped in collapsed structures.
Rescuers were shown surveying damage on a rural road that was blocked by fallen trees.
The footage showed the moment the quake struck Muroran, with its camera violently shaking and all city lights going out a moment later. In nearby Sapporo, a mudslide hit a road, leaving several cars half buried.
Some experts said the earthquake was likely caused by a series of slips on an inland active fault.
An active fault zone of more than 100 km in length runs north-south about 10 kilometers west of the epicenter. Although the Meteorological Agency says it is unclear whether the zone had something to do with the quake, the experts believe its displacement could be the cause.
Takashi Furumura, a professor of seismology at the University of Tokyo, said it is highly likely that the quake occurred in the southern part of the fault zone.
Furumura, who examined observed records of seismic waves, found that there were about three powerful shaking movements in a short period of time.
“Consecutive fault slips may have caused a strong shaking for a long time and triggered mudslides,” he said.
“The fault zone is massive and its structure is complicated,” said Yasuhiro Suzuki, a professor of geomorphology at Nagoya University.
But he noted there is not enough data on the southern part of the zone to tell if it has caused large-scale quakes in the past.
Collecting data on the southern part, which is more than 54 km in length, is difficult as it extends into the sea and partly runs under the seafloor, according to Suzuki.
Japan, situated on the “Ring of Fire” arc of volcanoes and oceanic trenches that partly encircles the Pacific Basin, accounts for about 20 percent of the world’s earthquakes of magnitude 6 or greater.