HONOLULU -- An earthquake measuring 6.5 shook the Hawaiian Islands on Sunday morning, according to the Pacific Tsunami Warning Center. The U.S. Geological Society is reporting the quake was 6.3.

It happened at 7:07 a.m. off the Waikoloa coast on the Big Island, according to scientists at the Pacific Tsunami Warning Center. The quake did not generate a tsunami, officials said. Aftershocks as strong as 5.8 have been reported.

Kona appears to have taken the brunt of the quake. Kona Community Hospital reported structural damage and multiple landslides were reported on the Hamakua Highway, officials said. Officials are concerned about the structural integrity of the hospital. Crews are evacuating patients to be safe.

Workers are also evacuating patients from the Honokaa Longterm Care Facility.

Officials said that boulders litter Kaahumanu Highway. Officials closed Highway 190 into Kailua-Kona because of debris on the road.

Callers from the Big Island told KITV that the shaking was so strong that people were knocked to the ground.

"It was an unusually large magnitude and in an unusual location," one scientist said.

A scientist at the Pacific Tsunami Warning Center said he believed this was the largest earthquake in Hawaii since 1983.

Residents reported feeling the shaking for more than a minute in some places. Residents in Niu Valley said the quake made items fall off shelves.

The quake knocked out power to all of Oahu. A Hawaiian Electric Co. spokesman said that the power would be restored over 10 to 12 hours on Oahu.

Some parts of the Big Island, Maui and Kauai had power restored. A Civil Defense spokesman said that power was at least partially knocked out on every island.

Maui suffered some landslides around Hana. Officials also closed Iao Valley Park until they could assess any damage in that area.

KITV crews are gathering information and will provide more as it becomes available.