Strong earthquakes hit Japan (6.0, 6.1, 6.0, Local tsunami advisory)

Associated Press and Prescott Herald ^ | 19 April 2007

[bd476]

Strong earthquakes hits Japan 2007/4

3 minutes ago

TOKYO - A strong earthquake struck near islands in southwestern Japan Friday, prompting authorities to warn that the area could be hit by a small tsunami.

The Meteorological Agency issued a tsunami advisory after the second and larger quake, saying that islands in the area could be hit by waves as high 18 inches.

People living on the island were being warned to stay away from the coast.

Miyakojima is about 1,130 miles southwest of Tokyo. Japan is one of the world‘s most earthquake-prone countries.

[SevenofNine]

Godzilla alert???

[bd476]

5.1 2007/04/20 03:00:58 25.664 125.380 10.0 Southwestern Ryukyu Islands, Japan

5.9 2007/04/20 02:23:34 25.633 125.044 10.0 Southwestern Ryukyu Islands, Japan

6.1 2007/04/20 01:45:57 25.739 125.222 10.0 Southwestern Ryukyu Islands, Japan

5.6 2007/04/20 00:31:07 25.740 125.080 57.5 Southwestern Ryukyu Islands, Japan

6.0 2007/04/20 00:26:46 25.664 125.103 50.4 Southwestern Ryukyu Islands, Japan

[pillut48]

USGS Earthquake Details Magnitude 5.9 # Date-Time Friday, April 20, 2007 at 02:23:34 (UTC) = Coordinated Universal Time # Friday, April 20, 2007 at 11:23:34 AM = local time at epicenter Time of Earthquake in other Time Zones Location 25.633°N, 125.044°E Depth 10 km (6.2 miles) set by location program Region SOUTHWESTERN RYUKYU ISLANDS, JAPAN Distances 160 km (100 miles) NNE of Ishigaki-jima, Ryukyu Islands, Japan 270 km (165 miles) WSW of Naha, Okinawa, Japan 340 km (210 miles) ENE of Su-ao, Taiwan 1785 km (1110 miles) SW of TOKYO, Japan Location Uncertainty horizontal +/- 8.4 km (5.2 miles); depth fixed by location program Parameters Nst=127, Nph=127, Dmin=365.2 km, Rmss=1.32 sec, Gp= 72°, M-type=body magnitude (Mb), Version=6 Source USGS NEIC (WDCS-D) Event ID us2007bjak

[pillut48]

Red= Last Hour Orange= Day Yellow= Week

[bd476]

Thanks for your help, Pillut48. I’m on a borrowed computer and without all my earthquake macros and info.

[goodnesswins]

This is Okinawa, right?

[Strategerist]

Okinawa is the Island with “Naha” under it on the map.

[bd476]

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[pillut48]

Glad to help anytime! I’m grabbing stuff from the USGS site.

[goodnesswins]

Thanks....are they likely to be affected by a sunami? (We have an exchange student friend there whose father is a fisherman....which means they live ON the water, basically.

[Strategerist]

There have been some really big tsunamis in the Southern Ryukus, but not for a while.

Okinawa is a steep and mountainous island so you’re only in danger right on the water and it’s possible to get high enough with any sort of warning at all.

You don’t see damaging tsunami from earthquakes this small, really. However it’s a pretty significant swarm.

Could be foreshocks, but they’re not on the subduction zone, (which is on the Pacific side of the Ryukus) but in the backarc basin, so a really huge quake doesn’t seem likely.

[bd476]

Magnitude 6.1 - SOUTHWESTERN RYUKYU ISLANDS, JAPAN

2007 April 20 01:45:56 UTC

Earthquake Details

Magnitude	6.1
Date-Time	Friday, April 20, 2007 at 01:45:56 (UTC) = Coordinated Universal Time Friday, April 20, 2007 at 10:45:56 AM = local time at epicenter
Location	25.739°N, 125.222°E
Depth	10 km (6.2 miles) set by location program
Region	SOUTHWESTERN RYUKYU ISLANDS, JAPAN
Distances	180 km (110 miles) NE of Ishigaki-jima, Ryukyu Islands, Japan 250 km (155 miles) W of Naha, Okinawa, Japan 360 km (225 miles) ENE of Su-ao, Taiwan 1770 km (1100 miles) SW of TOKYO, Japan
Location Uncertainty	horizontal +/- 8 km (5.0 miles); depth fixed by location program
Parameters	Nst= 54, Nph= 54, Dmin=385 km, Rmss=1.1 sec, Gp= 43°, M-type=body magnitude (Mb), Version=6
Source	USGS NEIC (WDCS-D)
Event ID	us2007bjai

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URL: http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2007bjai.php
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Page Last Modified: April 19, 2007 7:34:13 PM.

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[CrappieLuck]

18 Inch Tsunami?

[Strategerist]

That actually would be enough to knock boats around in a harbor, tear some from piers, etc.

[Ramius]

An 18 inch Tsunami *at sea* could be orders of magnitude greater when striking shore. Is that what they mean?

[bannie]

Tsunamette

[bd476]

CrappieLuck wrote: 18 Inch Tsunami?"

18 inches height times over 100 meters long is a significant increased volume of water if there is shoreline sloughing off. Some people assume that all tsunamis begin as gigantic waves, which is possible, yet an eventual catastrophic tsunami may begin out mid-ocean as a few inches of increased water height then as it approaches the shoreline, increase to damaging size.

I'm having some computer problems and have yet to confirm the tsunami through the tsunami bulletins.

[sushiman]

” Miyakojima is about 1,130 miles southwest of Tokyo “

Osaka and Fukuoka closer but of course most Americans haven’t a clue where these cities are in tiny Japan ...hence the TOKYO reference ...

[Strategerist]

An 18 inch Tsunami *at sea* could be orders of magnitude greater when striking shore. Is that what they mean?

No.

When tsunami warnings are issued, it's ALWAYS for the possible size AT A SHORELINE, NOT in the open ocean.

It would be a waste of time otherwise with people on shore being forced to guess in their heads at the height where they are.