Magnitude 8.1 - NORTH OF MACQUARIE ISLAND

USGS Earthquake Hazards ^ | 2004 December 23 14:59:04 UTC Thursday, December 23, 2004 | USGS

[bd476]

Magnitude 8.1 - NORTH OF MACQUARIE ISLAND
2004 December 23 14:59:04 UTC

Preliminary Earthquake Report
U.S. Geological Survey, National Earthquake Information Center
World Data Center for Seismology, Denver

A great earthquake occurred at 14:59:04 (UTC) on Thursday, December 23, 2004. The magnitude 8.1 event has been located NORTH OF MACQUARIE ISLAND. (This event has been reviewed by a seismologist.)

Magnitude	8.1
Date-Time	Thursday, December 23, 2004 at 14:59:04 (UTC) = Coordinated Universal Time Friday, December 24, 2004 at 1:59:04 AM = local time at epicenter
Location	50.240°S, 160.133°E
Depth	10 km (6.2 miles) set by location program
Region	NORTH OF MACQUARIE ISLAND
Distances	420 km (260 miles) W of Auckland Island, New Zealand 495 km (305 miles) N of Macquarie Island, Australia 1515 km (940 miles) SW of WELLINGTON, New Zealand 1890 km (1170 miles) SSE of CANBERRA, A.C.T., Australia
Location Uncertainty	horizontal +/- 12.1 km (7.5 miles); depth fixed by location program
Parameters	Nst=126, Nph=126, Dmin=>999 km, Rmss=1.33 sec, Gp= 25°, M-type=moment magnitude (Mw), Version=7
Source	USGS NEIC (WDCS-D)
Event ID	ussjal

[bd476]

Regarding Tsunamis:

"EVALUATION

THIS EARTHQUAKE IS LOCATED OUTSIDE THE PACIFIC. NO TSUNAMI THREAT EXISTS TO COASTLINES IN THE PACIFIC.

HOWEVER - THIS EARTHQUAKE HAS THE POTENTIAL TO GENERATE A WIDELY DESTRUCTIVE TSUNAMI IN THE SEA NEAR THE EARTHQUAKE. AUTHORITIES IN THAT REGION SHOULD BE AWARE OF THIS POSSIBILITY.

THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT UNLESS ADDITIONAL INFORMATION BECOMES AVAILABLE.

THE WEST COAST/ALASKA TSUNAMI WARNING CENTER WILL ISSUE BULLETINS FOR ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA."

[bd476]

Ping.

[bd476]

The New Zealand Herald

Sharp quake wakes South Islanders

24.12.04 1.00pm

An earthquake this morning under the south Tasman Sea was the largest in the world since 2001 but it did little more than wake people up in the south of the South Island.

Latest estimates from Geological and Nuclear Sciences (GNS) suggested the 3.58am earthquake was centred 430km west of the Auckland Islands, southwest of New Zealand, at a depth of 10km, and may have been as much as 8.1 on the Richter scale.

"It was enough to wake me up," Senior Sergeant Neil Cruickshank of Invercargill Police told NZPA. "It was reasonably prolonged but it felt about half the strength of the one we had a few weeks ago."

That earthquake, on November 23, was of a smaller magnitude -- 7.2 on the Richter scale -- but was only about 70km off the Fiordland coast.

Mr Cruickshank was not aware of any earthquake damage caused in the area today.

Earlier estimates suggested today's earthquake was also 7.2 on the Richter scale, located 380km north of Macquarie Island at a 33km depth.

"We now have it recorded at 7.3 but it's difficult for us to measure because it was so far away from us," GNS duty seismologist Ken Gledhill said.

"But international data from institutions like the US Geological Survey suggests it was 8.1, which in our measurements is a great earthquake."

More than 80 people logged on to the GNS website to say they felt the earthquake, though after the November 23 earthquake there had been more than 800 reports, Mr Gledhill said.

Today's quake was felt in Tasmania, causing buildings in parts of the state to shake for up to 15 seconds. No one was injured.

- NZPA

[bd476]

"An earthquake this morning under the south Tasman Sea was the largest in the world since 2001 but it did little more than wake people up in the south of the South Island."

It must be something in the air or water which makes Kiwis impervious to an 8.1 quake. :)

[bd476]

Magnitude 8 and Greater Earthquakes Since 1990

Earthquakes Magnitude 8.0 and Greater Since 1990

	Year	Month	Day	Time UTC	Latitude	Longitude	Depth (km)	Magnitude	Region
1	1994	06	09	00:33:16.2	-13.841	-67.533	631	8.2	Northern Bolivia
2	1994	10	04	13:22:55.8	43.773	147.321	14	8.3	Kuril Islands
3	1995	07	30	05:11:23.6	-23.340	-70.294	46	8.0	Near Coast of Northern Chile
4	1995	10	09	15:35:53.9	19.055	-104.205	33	8.0	Near Coast of Jalisco, Mexico
5	1996	02	17	05:59:30.5	-0.891	136.952	33	8.2	Irian Jaya Region, Indonesia
6	1998	03	25	03:12:25.0	-62.877	149.527	10	8.1	Balleny Islands Region
7	2000	11	16	04:54:56.7	-3.980	152.169	33	8.0	New Ireland Region, P.N.G.
8	2001	06	23	20:33:14.1	16.265	-73.641	33	8.4	Near Coast of Peru
9	2003	09	25	19:50:06.3	41.815	143.910	27	8.3	Hokkaido, Japan Region
10	2004	12	23	14:59:04.3	-50.240	160.133	10	8.1	North of Macquarie Island

South Latitudes and West Longitudes are indicated by NEGATIVE numbers.

Source: USGS NEIC PDE catalog; Data are preliminary.

[Strategerist]

It must be something in the air or water which makes Kiwis impervious to an 8.1 quake. :)

Distance.

[bd476]

[Lokibob]

Reported y-day morning on FR as a 7.9.

[Strategerist]

Takes time to analyze a strong quake. Especially one in a remote area.

[Lokibob]

I agree. I just wanted to point out that there was only one EQ of this magnitude in that area, and it was y-day morning.

This was a great post, especially since they raised the mag estimate.

[Lokibob]

 

Here is what it looked like on the seismometer I watch in Utah.  Look at 1517 UT (right side).  All the waves following the EQ are echos.  The earth rang like a bell for an hour after the EQ.

 

 

 

[xp38]

Surfs Up!!!

[Aracelis]

A moderate earthquake occurred at 05:31:44 (UTC) on Friday, December 24, 2004. The magnitude 5.5 event has been located NORTH OF MACQUARIE ISLAND

Still shakin'...

[bd476]

Surf's up again.

[vaimaanga]

Kia Orana from the Cook Islands.

Is there a possibility that a tidal wave generated by the earth quake 'Magnitude 8.1 - NORTH OF MACQUARIE ISLAND' on Dec 23 would have hit the island of Aitutaki, location
S 18° 49' 51" - W 159° 45' 51" on DEC 23, 9:30am HST, approx 5 hours after the event occurent near Macquarie.

That morning i was kayaking near the reef when big waves out of nowhere hit the reef, turned the kayak over and washed me right over it. The subsequent waves and surge were so strong that i was unable to paddle back to the island and i was rescued by a barge which then also had problems passing a relatively large passage back into the lagoon. People ashore reported having to relocate property to prevent it being washed away by 'freak waves'.

In view of the unprecedented desaster that hit SE Asia this seems a laughable incident, yet it would be interesting to know.

Thanks

Marcus Gleinig
Rarotonga
Cook Islands