A powerful magnitude-7.0 earthquake struck off the coast of southern Japan on Sunday, killing an elderly woman and injuring at least 381 people, damaging buildings and leaving residents shaken by aftershocks. Authorities issued a tsunami warning, but it was later canceled.

The temblor, which hit west of Kyushu Island (search) at 10:53 a.m. (0153 GMT), was centered at an "extremely shallow" depth of 5.5 miles below the ocean floor, the Japanese Meteorological Agency (search) said. Nearly 80 aftershocks followed — at least one a magnitude-4.2 quake.

Officials reported water and gas main breaks and power blackouts. Local and bullet train railway service was halted, after an automatic safety mechanism was triggered by the tremors, public broadcaster NHK reported. Telephone service in the southern prefecture was jammed.

Minutes after the shaking began, the agency warned of the possibility of 20-inch tsunami waves triggered by the seismic activity, and cautioned residents near the water to move to higher ground. But an hour after the quake, the agency said there was no danger of tsunami.

"There may be some disturbance of the ocean's surface, but we aren't worried about tsunami damage," said Masahiro Yamamoto of the Meteorological Agency.

Yamamoto predicted strong aftershocks measuring up to magnitude-6 would continue.

The death of a 75-year-old woman, who was hospitalized after a wall fell on her in southern Fukuoka city, became the first casualty of the quake, a Fukuoka prefectural (state) government spokesman said on condition of anonymity.

At least 381 people, most in hard-hit Fukuoka (search) prefecture, were injured, some struck by toppling cabinets, items falling off shelves or shattered glass, and two were burned by a cooking stove, NHK said.

Authorities in Fukuoka, 560 miles southwest of Tokyo, have confirmed 107 injuries, 15 of them serious, according to the prefectural government's Web site. Ten people in neighboring Saga prefecture were injured, a prefectural government official said.

In Saga prefecture's Okawa city, a 56-year-old man suffered broken bones after trying to jump to safety from the second floor of his home, the official said. One person was reportedly rescued after being pinned inside a fallen home.

"We have had frightened residents coming to the store because their own homes are shaking with every aftershock," said Shigeru Harada, a manager at convenience store Lawson in Fukuoka city.

Authorities said landslides had occurred around Fukuoka, Saga and Nagasaki prefectures.

Located along the Pacific Ocean's seismically active "Ring of Fire," Japan is one of the world's most earthquake-prone countries.

It is also one of the best prepared for a major quake. Tough requirements making buildings quake-safe and frequent disaster drills probably contributed to keep injuries and structural damage to a minimum in Sunday's temblor.

About 1,000 residents in Fukuoka prefecture evacuated their homes to stay in temporary shelters for the evening, including some 400 residents of Genkai island — nearly half of the population of the tiny island off the coast of Kyushu.

Eight people injured when homes and buildings collapsed were airlifted to hospitals in Fukuoka city, the Fukuoka government spokesman said. About 120 Japanese troops arrived Sunday to help with rescue and aid disbursement efforts.

A Fukuoka prefectural police spokesman said the initial jolt, which lasted about 30 seconds, made it difficult to stand.

NHK showed tall office buildings and street lamps in the center of Fukuoka, nearest the epicenter, shaking violently. In residential areas, cracks appeared in sidewalks and parts of retaining walls flaked off.

Authorities said landslides had been triggered around Fukuoka, Saga and Nagasaki prefectures.

Kyushu Island is separated from South Korea by a narrow strait of water, and the quake was felt about 130 miles away in South Korea's port city of Busan, where it briefly shook buildings. No damage was immediately reported, a police spokesman in Busan said.

A magnitude-7 quake can cause tremendous damage in populated areas, either directly or by triggering tsunami, which are distinguished from normal coastal surf by their great length and speed.

On Oct. 23, a magnitude-6.8 earthquake struck Niigata, about 160 miles northwest of Tokyo, killing 40 people and damaging more than 6,000 homes. The jolt was the deadliest to hit Japan since 1995, when a magnitude-7.3 quake killed 6,433 people in the western city of Kobe.

On Dec. 26, a 9.0-magnitude quake triggered a massive tsunami that devastated Asian and African coastlines in nearly a dozen nations, killing at least 175,000 people.