Magnitude 6.3 Earthquake Strikes Hawaii

[Kevy Baby]

HONOLULU (AP) - An earthquake with a preliminary magnitude of 6.3 struck Hawaii early Sunday morning, waking up residents and knocking out power.

The U.S. Geological Survey also reported several aftershocks, including one measuring a magnitude of 5.8. No damage reports were immediately available.

The quake occurred at 7:07 a.m. local time, 10 miles north-northwest of Kailua Kona, a town on the west coast of the Big Island, said Don Blakeman, a geophysicist at the National Earthquake Information Center, part of the U.S. Geological Survey.

Blakeman said researchers were still trying to ascertain how many aftershocks struck and how large.

Blakeman said there was no risk of a Pacific-wide tsunami, but a possibility of significant wave activity in Hawaii.

The quake occurred about 155 miles to the southeast of Honolulu, the state capital, in Oahu.

Actually, that is the whole story so far. Hopefully there isn't much more to report.

[Alex]

Here's the map. What is odd is that for the first hour after the quake it was showing two smaller quakes (4.9 and 4.6).

THe local news radio station initially reported 6.9 and then later corrected to match the USGS. But now the USGS is saying 6.3. Usually their maps are very reliable (I've seen the data appear on the site within a minute of feeling a quake), so I wonder what went wrong.

Listening to the local news was a lesson in geography as we were told the earthquake was in the island of Oahu and that they were receiveing reports from the island of Honolulu as well.

[tracilicious]

How powerful is that an earthquake in comparison to really destructive earthquakes? What's a big deal as far as quakes go?

[Alex]

6.3 is plenty strong to do significant damage depending on local conditions. Fortunately the Big Island is the kind of solid ground that generally does better in strong earthquakes than other compositions and it sounds like damage isn't too bad.

For comparison the Northridge quake in '94 was 6.7 and the Loma Prieta (San Francisco) quake in 1989 was 6.9.

The Richter Scale is a log10 scale so a 7.0 has ten times the shaking as a 6.0 (and 32 times the energy) so 6.3 generally won't be catastrophic. The strongest earthquake in Hawaii was 7.9 in 1868. At 6.3, this one is the largest quake in the United States so far this year but there were three larger ones in 2005.

[tracilicious]

Thanks for the info.

How big will the quake be that they predict will rip California away from the mainland? (Or is that theory abandoned now?)

[Alex]

Well, it is only a small part of California that would rip away and that will happen with time, not requiring a massive earthquake.

And that is the problem with the Richter scale (and why seismologists don't really care for it). It measures one feature of earthquakes (shaking) that isn't necessarily useful for measuring outcomes or the nature of the quake.

Depending on where and how deep it happens, a 6.3 earthquake can be very different things.

[Strangler Lewis]

In 1989, we lived in an apartment on top of a hill in the Western Addition of San Francisco. We had all our glasses on open shelves in the kitchen. Though it felt like we were riding a jackhammer, somehow we rode the wave and lost just one champagne flute. Our neighbors, whose kitchen was oriented differently, had everything come down. Still a better outcome than some of those who lived near the marina whose buildings came down around them. All around, still better than Iran, Armenia, etc.

[Moonliner]

We just stayed in Kona this summer. I hope things are not too bad.

I still have a good number of Hawaii/kona bookmarks. Most of the sites, such as the Mauna Kea Observatories are offline at the moment. One discussion board has a few comments primarily about dishes falling off the shelves and the like.

[Snowflake]

Originally Posted by Strangler Lewis

In 1989, we lived in an apartment on top of a hill in the Western Addition of San Francisco. We had all our glasses on open shelves in the kitchen. Though it felt like we were riding a jackhammer, somehow we rode the wave and lost just one champagne flute. Our neighbors, whose kitchen was oriented differently, had everything come down. Still a better outcome than some of those who lived near the marina whose buildings came down around them. All around, still better than Iran, Armenia, etc.

We're just above you on the edge of Pacific Heights at Cal/Octavia. We're on bedrock and had nary a crooked picture in 1989. I was just coming out of work and waiting for a 1 California bus in front of the Hyatt. It was the strongest and longest quake I can remember, it sure felt a lot longer than 15 seconds. I grabbed the bus pole to stop from falling over.

[Kevy Baby]

My dad and his wife are in Hawaii. We got this email from him about an hour-and-a-half ago:

We are on Maui now and did really feel it. We are on the 5th floor and lost power (including cell phones and wireless laptop) for about 2 1/2 hours. We are back up now but they are asking that we NOT use our cell phones yet.

Which explains why I couldn't reach him on his cell!

Originally Posted by tracilicious

How big will the quake be that they predict will rip California away from the mainland? (Or is that theory abandoned now?)

Further research now indicates that everything east of the San Andreas fault will fall into the Atlantic Ocean.