8.8-magnitude earthquake hits central Chile

[Joe-Nathan]

I bet nobody even noticed the Seiche.

WHAT IS A SEICHE?

From Wikipedia, the free encyclopedia

Quote: "Seiche" is also a French term for a type of cuttlefish (Sepiida).

A seiche (pronounced /ˈseɪʃ/ "saysh") is a standing wave in an enclosed or partially enclosed body of water. Seiches and seiche-related phenomena have been observed on lakes, reservoirs, swimming pools, bays, and seas. The key requirement for formation of a seiche is that the body of water be at least partially bounded, allowing the formation of the standing wave.

The term was promoted by the Swiss hydrologist François-Alphonse Forel in 1890, who was the first to make scientific observations of the effect in Lake Geneva, Switzerland.[1] The word originates in a Swiss French dialect word that means "to sway back and forth", which had apparently long been used in the region to describe oscillations in alpine lakes
Causes and nature of seiches
A standing wave (red) depicted as a sum of two propagating waves traveling in opposite directions (green and blue).

Seiches are often imperceptible to the naked eye, and observers in boats on the surface may not notice that a seiche is occurring due to the extremely long wavelengths. The effect is caused by resonances in a body of water that has been disturbed by one or more of a number of factors, most often meteorological effects (wind and atmospheric pressure variations), seismic activity or by tsunamis[2]. Gravity always seeks to restore the horizontal surface of a body of liquid water, as this represents the configuration in which the water is in hydrostatic equilibrium. Vertical harmonic motion results, producing an impulse that travels the length of the basin at a velocity that depends on the depth of the water. The impulse is reflected back from the end of the basin, generating interference. Repeated reflections produce standing waves with one or more nodes, or points, that experience no vertical motion. The frequency of the oscillation is determined by the size of the basin, its depth and contours, and the water temperature.

The longest natural period[3] for a seiche in an enclosed rectangular body of water is usually represented by the Merian formula:

\mbox{Period}(T) = \frac{2L}{\sqrt{g h}}

where L is the length, h the average depth of the body of water, and g the acceleration of gravity.[4]

Higher order harmonics are also observed. The period of the second harmonic will be half the natural period, the period of the third harmonic will be a third of the natural period, and so forth.

[Joe-Nathan]

ROLLTIDE Wrote:http://www.hawaiinewsnow.com/Global/cate...menu55_1_1

This has the potential to be the most videoed Tsunami in history, but they are calling for 6-8 foot wave at its max.

Not a surfable wave...

[Joe-Nathan]

BULLETIN
TSUNAMI MESSAGE NUMBER 17
NWS PACIFIC TSUNAMI WARNING CENTER EWA BEACH HI
1025 AM HST SAT FEB 27 2010

Quote:TO - CIVIL DEFENSE IN THE STATE OF HAWAII

SUBJECT - TSUNAMI WARNING SUPPLEMENT

A TSUNAMI WARNING CONTINUES IN EFFECT FOR THE STATE OF HAWAII.

AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS

ORIGIN TIME - 0834 PM HST 26 FEB 2010
COORDINATES - 36.1 SOUTH 72.6 WEST
LOCATION - NEAR COAST OF CENTRAL CHILE
MAGNITUDE - 8.8 MOMENT

MEASUREMENTS OR REPORTS OF RECENT TSUNAMI WAVE ACTIVITY

GAUGE LOCATION LAT LON TIME AMPL PER
------------------- ----- ------ ----- --------------- -----
LOTTIN PT NZ 37.6S 178.2E 1934Z 0.15M / 0.5FT 10MIN
RAROTONGA CK 21.2S 159.8W 1918Z 0.32M / 1.0FT 06MIN
CABO SAN LUCAS MX 22.9N 109.9W 1833Z 0.36M / 1.2FT 12MIN
DART TONGA 51426 23.0S 168.1W 1844Z 0.04M / 0.1FT 30MIN
HIVA OA MARQUESAS 9.8S 139.0W 1741Z 1.79M / 5.9FT 12MIN
PAPEETE TAHITI 17.5S 149.6W 1810Z 0.16M / 0.5FT 10MIN
NUKU HIVA MARQUESAS 8.9S 140.1W 1745Z 0.95M / 3.1FT 04MIN
MANZANILLO MX 19.1N 104.3W 1705Z 0.32M / 1.0FT 24MIN
DART MANZANILLO 434 16.0N 107.0W 1611Z 0.07M / 0.2FT 24MIN
ACAPULCO MX 16.8N 99.9W 1549Z 0.16M / 0.5FT 24MIN
RIKITEA PF 23.1S 134.9W 1559Z 0.15M / 0.5FT 22MIN

LAT - LATITUDE (N-NORTH, S-SOUTH)
LON - LONGITUDE (E-EAST, W-WEST)
TIME - TIME OF THE MEASUREMENT (Z IS UTC IS GREENWICH TIME)
AMPL - TSUNAMI AMPLITUDE MEASURED RELATIVE TO NORMAL SEA LEVEL.
IT IS ...NOT... CREST-TO-TROUGH WAVE HEIGHT.
VALUES ARE GIVEN IN BOTH METERS(M) AND FEET(FT).
PER - PERIOD OF TIME IN MINUTES(MIN) FROM ONE WAVE TO THE NEXT.

CURRENT RANGE OF FORECAST INITIAL WAVE ARRIVAL TIME AND MAXIMUM
WAVE AMPLITUDES MEASURED FROM CREST TO TROUGH.

[SIZE="3"][COLOR="DarkRed"] HILO 1105AM HST 2.1-2.5 METERS
HONOLULU 1137AM HST 0.5-0.7 METERS
KAHULUI 1126AM HST 1.1-3.0 METERS
NAWILIWILI 1142AM HST 0.9-1.4 METERS
HALEIWA 0.5-1.1 METERS
KAWAIHAE 0.6-1.6 METERS[/COLOR][/SIZE]

THESE ARE ONLY ESTIMATES...ACTUAL VALUES MAY DIFFER.

EVALUATION

A TSUNAMI HAS BEEN GENERATED THAT COULD CAUSE DAMAGE ALONG
COASTLINES OF ALL ISLANDS IN THE STATE OF HAWAII. URGENT ACTION
SHOULD BE TAKEN TO PROTECT LIVES AND PROPERTY.

A TSUNAMI IS A SERIES OF LONG OCEAN WAVES. EACH INDIVIDUAL WAVE
CREST CAN LAST 5 TO 15 MINUTES OR MORE AND EXTENSIVELY FLOOD
COASTAL AREAS. THE DANGER CAN CONTINUE FOR MANY HOURS AFTER THE
INITIAL WAVE AS SUBSEQUENT WAVES ARRIVE. TSUNAMI WAVE HEIGHTS
CANNOT BE PREDICTED AND THE FIRST WAVE MAY NOT BE THE LARGEST.
TSUNAMI WAVES EFFICIENTLY WRAP AROUND ISLANDS. ALL SHORES ARE AT
RISK NO MATTER WHICH DIRECTION THEY FACE. THE TROUGH OF A TSUNAMI
WAVE MAY TEMPORARILY EXPOSE THE SEAFLOOR BUT THE AREA WILL
QUICKLY FLOOD AGAIN. EXTREMELY STRONG AND UNUSUAL NEARSHORE
CURRENTS CAN ACCOMPANY A TSUNAMI. DEBRIS PICKED UP AND CARRIED
BY A TSUNAMI AMPLIFIES ITS DESTRUCTIVE POWER. SIMULTANEOUS HIGH
TIDES OR HIGH SURF CAN SIGNIFICANTLY INCREASE THE TSUNAMI HAZARD.

THE ESTIMATED ARRIVAL TIME IN HAWAII OF THE FIRST TSUNAMI WAVE IS

1105 AM HST SAT 27 FEB 2010

MESSAGES WILL BE ISSUED HOURLY OR SOONER AS CONDITIONS WARRANT.

[HarvestMoon]

http://hitsunami.info/

[Joe-Nathan]

Water is draining out of Hilo Bay. Water appears to have drop a couple of feet.

[ROLLTIDE]

water is returning to Hilo bay now

[Joe-Nathan]

Does anybody have any info on the possible Tsunami damage in Venture, CA?

[virgo10]

Joe-Nathan Wrote:Does anybody have any info on the possible Tsunami damage in Venture, CA?

Only thing I could find.

Quote:According to a report on Hawaiin televison the Tsunami has apparantly caused damage in the Ventura, CA area. Earlier today, a Tsunami was triggered off the coast of Chili as a result of a major earthquake in that country.

No confirmed reports of any damage so far in Ventura County other than the above named report. The effects of the tsunami are going to be felt up the California coastline, but the severity of it is not known. The effects of the tsunami are starting to hit Hawaii now.

Tune in to your local news station for up to date coverage.

http://www.gather.com/viewArticle.action...4697244816

[Joe-Nathan]

[SIZE="3"]Magnitude 4.4 - OKLAHOMA
2010 February 27 22:22:27 UTC [/SIZE]

Quote:Magnitude 4.4
Date-Time

* Saturday, February 27, 2010 at 22:22:27 UTC
* Saturday, February 27, 2010 at 04:22:27 PM at epicenter
* Time of Earthquake in other Time Zones

Location 35.623°N, 96.762°W
Depth 3.8 km (2.4 miles) (poorly constrained)
Region OKLAHOMA
Distances

* 5 km (3 miles) ENE (74°) from Sparks, OK
* 9 km (6 miles) S (179°) from Davenport, OK
* 15 km (9 miles) SE (130°) from Chandler, OK
* 35 km (22 miles) NNE (26°) from Shawnee, OK
* 72 km (44 miles) ENE (77°) from Oklahoma City, OK
* 314 km (195 miles) N (0°) from Dallas, TX

Location Uncertainty horizontal +/- 14.1 km (8.8 miles); depth +/- 3.8 km (2.4 miles)
Parameters NST= 61, Nph= 68, Dmin=72.1 km, Rmss=1.48 sec, Gp= 65°,
M-type="Nuttli" surface wave magnitude (mbLg), Version=7
Source

* USGS NEIC (WDCS-D)

Event ID us2010tfe4

[Joe-Nathan]

virgo10 Wrote:Only thing I could find.



http://www.gather.com/viewArticle.action...4697244816

Thank you.