The strongest earthquake in over 20 years struck the Hawaiian islands early Sunday.

Power was disrupted for more than 12 hours on Oahu, home to Honolulu, Waikiki, and Mac360’s web server.

The 6.6 magnitude quake caused massive blackouts on three islands, landslides on Hawaii, and forced thousands of visitors to flee their hotels.

There were no reports of casualties, though Mac360, running on a PowerMac G5 server in central Honolulu, was offline for 12 hours.

The quake struck the Big Island of Hawaii shortly after 7:00 AM HST, then again about five minutes later near the island of Maui.

Initial reports indicated that the quake’s center was approximately 10 miles offshore from Waikoloa, Hawaii on the Big Island.

Within minutes the quake rattled across Maui and Oahu-- all power to Honolulu, Maui, and Hawaii was disrupted.

The islands of Lanai, Kauai, and Molokai were unaffected.

Mac360’s server has battery backup power which lasted a full three hours. Electrical power to much of Honolulu was out for over 12 hours.

The site was restored to internet access at approximately 10:45 PM HST.

I just finished a full backup to the two servers we use for Mac360, using SuperDuper!. The Mac360 site runs on a PowerMac which we shut down about five minutes before battery power was depleted. The mail server runs on a Mac mini and remained online for another hour before losing battery power and shutting down.

As of 11:00 PM HST, power had been restored to most of Honolulu, though some central honolulu areas, and remote areas had yet to be restored. Oahu has three main generators, all of which stopped generating power and shut down after the seismic event early Sunday morning.

We’ll have a couple of more updates later Monday. For now, we’re busy cleaning out the refrigerator.

Quick Update on Mac360’s site status. Network Solutions, our Domain Name Service host, is experiencing major difficulties Tuesday. While http://www.mac360.com works fine, plain old mac360.com (without the “www”) does not work. Go figure. NetSol says the outage will be corrected within a few hours. That’s exactly what we heard when it happened a week ago.