[augie]

October 15, 2006, 4:00 PM EDT

HONOLULU -- A strong earthquake shook Hawaii early Sunday, causing a landslide that blocked a major highway on Hawaii Island and knocking out power across the state, authorities said.

The state Civil Defense had unconfirmed reports of injuries, but communication problems prevented more definite reports. People were also trapped in elevators in Oahu, authorities said.

Gov. Linda Lingle said in a radio interview with KSSK from Hawaii Island that she had no report of any fatalities. She said boulders fell on highways, rock walls collapsed and television had been knocked off stands.

"We were rocking and rolling," said Anne LaVasseur, who was on the second floor of a two-story, wood-framed house on the east side of the Big Island when the temblor struck. "I was pretty scared. We were swaying back and forth, like King Kong's pushing your house back and forth."

The quake hit 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.

The Pacific Tsunami Center reported a preliminary magnitude of 6.5, while the U.S. Geological Survey gave a preliminary magnitude of 6.3. It was followed by several strong aftershocks, including one measuring a magnitude of 5.8, the Geological Survey said.
AP

[kanaloa]

Just unbelievable. I just found out a few minutes ago about this... Yikes.

[mnemonicj]

I have friends on a honeymoon there.

[kanaloa]

<img src="http://www.pronetworks.org/main/images/blurb/local01.jpg">

I JUST hiked on that ridge this summer. That's just crazy.

No major injuries to report. I've been talking with dozens of folks in the islands. Kauai has the most power, Oahu is completey without power, Maui's power just came back on in places, and the Big Island has had massive landslides in places. Some roads are also impassible.

But everyone I've talked to is OK... the real problem now it the major storm system over the islands. It's causing flooding and further damage and it was going on last night, so they are getting a double whammy now.

[kanaloa]

Also FYI... this was likely NOT a lava movement issue like most EQ's in Hawaii. It was likely subsidance (sinking) of Mauna Kea and/or Kohala Mountain into the oceanic place.

[augie]

Also FYI... this was likely NOT a lava movement issue like most EQ's in Hawaii. It was likely subsidance (sinking) of Mauna Kea and/or Kohala Mountain into the oceanic place.

I can't even recall the last time a large earthquake hit the islands. It must be the subsidence of plates, as you said, (or subduction as I know the term) which I never knew even existed in that area. Oh well, learn something new everyday. Good to know that there wasn't that much damage and that your friends are fine.

[kanaloa]

The USGS guy said the largest they'd had since the 60's was a 4.8 but I don't think that's right. I think in 1990 they had a 6.4 on the Big Island. The Big Island has hundreds of EQ's daily, but 90% are lava movement deep under the islands. These EQ's (it may have actually been two) were what me and Augie are talking about, subsidence, and they are very rare in Hawaii. Kohala is an extinct volcano.

Mauna Kea and Hualalai (the next closest to the epicenter) are dormant. Mauna Loa and Kilauea are the two active volcanoes and they are on the other side of the island where the majority of EQ's happen.

[j8k3sp00n]

The USGS guy said the largest they'd had since the 60's was a 4.8 but I don't think that's right. I think in 1990 they had a 6.4 on the Big Island. The Big Island has hundreds of EQ's daily, but 90% are lava movement deep under the islands. These EQ's (it may have actually been two) were what me and Augie are talking about, subsidence, and they are very rare in Hawaii. Kohala is an extinct volcano.

Mauna Kea and Hualalai (the next closest to the epicenter) are dormant. Mauna Loa and Kilauea are the two active volcanoes and they are on the other side of the island where the majority of EQ's happen.

K,

Please tell us where this is taking place with respect to where you live or lived. I recall zeroing in on your place when we were doing the geographic challenges but that information has long since been archived(in my brain), perhaps forever.

Cheers!

Jim Jordan

[augie]

The USGS guy said the largest they'd had since the 60's was a 4.8 but I don't think that's right. I think in 1990 they had a 6.4 on the Big Island. The Big Island has hundreds of EQ's daily, but 90% are lava movement deep under the islands. These EQ's (it may have actually been two) were what me and Augie are talking about, subsidence, and they are very rare in Hawaii. Kohala is an extinct volcano.

Mauna Kea and Hualalai (the next closest to the epicenter) are dormant. Mauna Loa and Kilauea are the two active volcanoes and they are on the other side of the island where the majority of EQ's happen.

I sit corrected as subduction is where two plates are pushing against each other whereas subsidence is more akin to them pulling apart as I understand it. It's weird as Hawaii sits almost in the middle of the Pacific plate. Anyways, I'm learning a lot from this thread and Googling this, I see I need a few years to get the drift(of tectonic plates). As always, thanks for your expertise.

[kanaloa]

The USGS guy said the largest they'd had since the 60's was a 4.8 but I don't think that's right. I think in 1990 they had a 6.4 on the Big Island. The Big Island has hundreds of EQ's daily, but 90% are lava movement deep under the islands. These EQ's (it may have actually been two) were what me and Augie are talking about, subsidence, and they are very rare in Hawaii. Kohala is an extinct volcano.

Mauna Kea and Hualalai (the next closest to the epicenter) are dormant. Mauna Loa and Kilauea are the two active volcanoes and they are on the other side of the island where the majority of EQ's happen.

I sit corrected as subduction is where two plates are pushing against each other whereas subsidence is more akin to them pulling apart as I understand it. It's weird as Hawaii sits almost in the middle of the Pacific plate. Anyways, I'm learning a lot from this thread and Googling this, I see I need a few years to get the drift(of tectonic plates). As always, thanks for your expertise.

OK let me clarify a few things. Plates aren't what's at work under Hawaii. Hawaii is a 'hot spot.'

Subduction takes place near the Aluetian Islands and in a lot of places around the ring of fire in the Pacific. That's where the oceanic plate slips beneath a continental plate. Thus subduction and pretty nasty EQ's. You can also get volcanoes (typically explosive ones) on the continental side of the boundary (thus the volcanoes on the west coast of the US and Canada, like Mt. St. Helens). Subduction also can be a oceanic and oceanic plate, like the mariana trench. When continental plates collide like India and China you get the Himalayas.

Hawaii is formed by a hot spot in the Pacific plate, or a place where a plume of lava comes through the moving plate. Thus the plate moves above the hot spot in the earth. The Hawaiian islands form as this plate moves over the hot spot, eventually piggy-backing off to the north and west. Thus the islands that are west and north of the current hot spot (Kilauea and Lo'ihi, a seamount) are much much older than these current two.

The other major hot spot in the world is Yellowstone National Park.

The forces at play that likely caused this EQ were caused by subsidence or sinking into the crust, not subduction. It'd be like taking a piece of plywood and spanning it between two supports, then dumping rocks on it in the middle. It would bend down in the middle. The Hawaiian islands mass makes them sink into the crust. That's likely what caused this EQ, bc the EQ occured near older volcanic mountains, and not near the currently active ones.