HONOLULU -- A Waterloo Army Reserve officer was shaken out of her bed Sunday morning when an earthquake rocked the Hawaiian Islands.

Maj. Angela Douglas, a nurse stationed at Tripler Army Medical Center in Honolulu, called her mother, Lou Porter of Waterloo, shortly after the quake hit at 7:07 a.m. in Hawaii. It was just after noon in Iowa when Porter's phone rang.

"Something's wrong, my bed's shaking," Porter recalled her frantic daughter saying at the time. "She was still in bed and frightened to death."

Douglas wasn't injured in the 6.6- magnitude quake, centered just off the northeast side of the big island of Hawaii, which caused landslides and power blackouts throughout the island chain. Honolulu is on the island of Oahu, situated northeast of the quake's epicenter. Officials said it was the worst temblor in more than 20 years.

Stationed with the 4224 U.S. Army Hospital, Detachment 1, in Cedar Rapids, Douglas was called to active duty earlier this year. Instead of Iraq, she was sent to Hawaii about six months ago. It's not uncommon for reservists to fill in for active duty soldiers who are re-assigned to combat roles.

Douglas was unavailable for comment, so it's unclear if that occurred in her case. Her tour is scheduled for 18 months, Porter said.

"I was so thankful she got sent to Hawaii. ... I thought she would be safe there," Porter said.

The concerned mother watched news reports all day Sunday, periodically talking with Douglas as cellular phone reception allowed. Porter said she would keep her daughter updated on what was happening on Sunday while power was knocked out.

Douglas has been a nurse at Covenant Medical Center for about 20 years. On Monday morning, Porter said she received several phone calls from Covenant employees wondering about her daughter.

"Thank God nobody was killed or seriously hurt," Porter said.