Authorities hailed Japan's new earthquake alert system as a success Monday after it allowed officials to issue a tsunami warning just one minute after a magnitude 6.9 quake jolted the country's coast a day earlier.
The quake early Sunday killed one person and injured 214 others, but officials said the one-minute warning provided a potentially lifesaving edge over the three minutes required by the country's older alert system.
Strong aftershocks shook the region Monday, and authorities in the town of Wajima near the epicenter said a lack of safe drinking water had become a top concern.
Prime Minister Shinzo Abe promised to expedite aid. "There has been great damage ... The government will provide whatever aid the regions need," he told reporters late Monday.
Strong aftershocks measuring magnitudes 5.3 and 4.8 struck Monday, but there was no tsunami danger, Japan's Meteorological Agency said. The agency said aftershocks could continue for a week.
"A fairly big aftershock hit just minutes ago and I jumped out the door," said Tomio Maeda, manager of a convenience store in Anamizu town. "It's scary, I guess it's not over yet."
Sunday morning's quake struck undersea off central Japan, along the Noto peninsula that juts into the Sea of Japan. The earthquake toppled buildings, triggered landslides, cut electricity, snapped water mains and disrupted transportation throughout the region.
It also triggered a small tsunami about 15 centimeters (6 inches) tall that hit shore 36 minutes later.
Though the wave did not cause any damage, authorities were able to give an early warning because of a more sensitive earthquake detection system that Japan has been using since last October.
The new system can detect slight tremors that travel underground ahead of a larger quake, Meteorological Agency official Yosuke Igarashi said. Sunday's quake was the first time the system has been used to issue a tsunami warning.
"Before the new system went into effect, it took about three minutes to get out a tsunami alert. On Sunday, we were able to get the alert out within a minute, so I'd say it was a success," Igarashi said.
The Meteorological Agency expects the new system will reduce earthquake injuries and damage by allowing authorities to quickly shut down elevators and trains and rapidly evacuate factories, offices and other buildings.
Prime Minister Shinzo Abe told a parliamentary committee Monday the quake had knocked down at least 68 homes and partially destroyed another 164.
A 52-year-old woman was crushed to death by a falling stone lantern and at least 214 other people were injured, most of them hurt when they fell or were hit by falling objects and broken glass, officials said.
The Fire and Disaster Management Agency said most of the injuries and damage occurred in Wajima, about 310 kilometers (193 miles) northwest of Tokyo.
More than 4,000 households were without water, and damage to roads made it difficult to truck in supplies, city official Kazuharu Kaji told public broadcaster NHK.
"Water is in extremely short supply," Kaji said. "In particular, there are dialysis patients and others at local hospitals who may not be able to receive treatment because of the shortage."
The affected area had not suffered a major quake since 1933.
Electricity had been largely restored Monday, reports said.
Japan sits atop four tectonic plates and is one of the world's most earthquake-prone countries, reports AP.
In October 2004, a magnitude-6.8 earthquake hit northern Japan, killing 40 people and damaging more than 6,000 homes. It was the deadliest to hit Japan since 1995, when a magnitude-7.2 quake killed 6,433 people in the western city of Kobe.