New Zealand Earthquakes

[Jacob]

Been a busy day out in the Pacific, with a 6.9, 7.4, and the latest being an 8.1 hitting NE of New Zealand today. All within a 6-7 hour window.

The latest quake, the 8.1, has prompted Tsunami watches across much of the Pacific.

 

[warneagle]

Any word yet on whether either of the first two actually triggered any tsunami activity? I saw there were warnings and evacuations in New Zealand but never heard of any damage or anything.

 

[bjdeming]

Any word yet on whether either of the first two actually triggered any tsunami activity? I saw there were warnings and evacuations in New Zealand but never heard of any damage or anything.

There have been three biggies so far and here is the current warning for NZ. The first waves were expected about two hours ago:

The first waves may reach New Zealand in the areas around LOTTIN POINT at approximately 9:49am New Zealand Daylight Time.

The severity of currents and surges will vary within a particular coastal area and over the period this warning is in effect.

The first wave may not be the largest. Tsunami activity will continue for several hours and the threat must be regarded as real until this warning is cancelled.

Per PTWC, waves are coming in - check this page for latest.

Per one of the general-threat messages for the 8.1 (the 27,000-noodle one ):

TSUNAMI THREAT FORECAST
-----------------------

* TSUNAMI WAVES REACHING MORE THAN 3 METERS ABOVE THE TIDE
LEVEL ARE POSSIBLE ALONG SOME COASTS OF

KERMADEC ISLANDS.


* TSUNAMI WAVES REACHING 1 TO 3 METERS ABOVE THE TIDE LEVEL ARE
POSSIBLE ALONG SOME COASTS OF

NEW CALEDONIA... AND VANUATU.


* TSUNAMI WAVES REACHING 0.3 TO 1 METERS ABOVE THE TIDE LEVEL
ARE POSSIBLE FOR SOME COASTS OF

ANTARCTICA... AUSTRALIA... CHILE... COLOMBIA... COOK
ISLANDS... COSTA RICA... ECUADOR... FIJI... FRENCH
POLYNESIA... KOSRAE... MEXICO... NAURU... NEW ZEALAND...
NICARAGUA... PANAMA... PERU... PITCAIRN ISLANDS...
POHNPEI... SAMOA... SOLOMON ISLANDS... TONGA... AND WALLIS
AND FUTUNA.


* TSUNAMI WAVES ARE FORECAST TO BE LESS THAN 0.3 METERS ABOVE
THE TIDE LEVEL FOR THE COASTS OF

AMERICAN SAMOA... CHINA... CHUUK... EL SALVADOR... GUAM...
GUATEMALA... HAWAII... HONDURAS... HOWLAND AND BAKER...
INDONESIA... JAPAN... JARVIS ISLAND... JOHNSTON ATOLL...
KIRIBATI... MALAYSIA... MARSHALL ISLANDS... MIDWAY
ISLAND... NIUE... NORTHERN MARIANAS... NORTHWESTERN
HAWAIIAN ISLANDS... PALAU... PALMYRA ISLAND... PAPUA NEW
GUINEA... PHILIPPINES... RUSSIA... TAIWAN... TOKELAU...
TUVALU... WAKE ISLAND... AND YAP.


* ACTUAL AMPLITUDES AT THE COAST MAY VARY FROM FORECAST
AMPLITUDES DUE TO UNCERTAINTIES IN THE FORECAST AND LOCAL
FEATURES. IN PARTICULAR MAXIMUM TSUNAMI AMPLITUDES ON ATOLLS
AND AT LOCATIONS WITH FRINGING OR BARRIER REEFS WILL LIKELY
BE MUCH SMALLER THAN THE FORECAST INDICATES.

* FOR OTHER AREAS COVERED BY THIS PRODUCT A FORECAST HAS NOT
YET BEEN COMPUTED. THE FORECAST WILL BE EXPANDED IF
NECESSARY IN SUBSEQUENT PRODUCTS.

 

[bjdeming]

The only documented wave I've read about thus far is 0.2 feet at a place in Tonga, I believe. Watches are being cancelled in several countries. But the threat still will go on for hours yet.

An update from Sydney: https://amp.smh.com.au/world/oceani...uake-strikes-new-zealand-20210305-p577z1.html

and a reliable NZ update source.

 

[bjdeming]

Here is that graph, but of course the page is opening slowly.

 

[bjdeming]

This tweeter is a West Coast seismologist. ? where to find gauge online.

 

[WesL]

@bjdeming I am so glad you a member of our site to help explain geological events! On a side note.. I think you are going to LOVE where our next memorial weather station is going. Just purchased your Volcano book!

The Decade Volcanoes and Us, Deming, B. J. - Amazon.com

The Decade Volcanoes and Us - Kindle edition by Deming, B. J.. Download it once and read it on your Kindle device, PC, phones or tablets. Use features like bookmarks, note taking and highlighting while reading The Decade Volcanoes and Us.

amzn.to

 

[bjdeming]

@bjdeming I am so glad you a member of our site to help explain geological events! On a side note.. I think you are going to LOVE where our next memorial weather station is going. Just purchased your Volcano book!

The Decade Volcanoes and Us, Deming, B. J. - Amazon.com

The Decade Volcanoes and Us - Kindle edition by Deming, B. J.. Download it once and read it on your Kindle device, PC, phones or tablets. Use features like bookmarks, note taking and highlighting while reading The Decade Volcanoes and Us.

amzn.to

That's so kind of you, Wes. Thank you, and please tell me you're putting it on a volcano ...wait, in the South? Well, it's possible, I guess, even in Arkansas.

Anyway, just wanted to share the last tsunami listing: there were many, all the way up to Hawaii (miniscule) and Mexico, but fortunately it wasn't another 2004/2011 disaster anywhere. Think Norfolk Island got a two-footer.

It might be worthwhile to keep an eye on Raoul Island volcano, since apparently (from tweets read yesterday) the tidal gauge there went down not long after the last 7-pointer's wave came in, raising questions about possible destructive effects from the M8.1's wave.

There's a research station there, but fortunately no one was on the island at the time per COVID restrictions. Double fortunately, as there's now a tropical cyclone bearing down on it.

From the little reading I've done, earthquakes don't cause eruptions, except when they do -- that is, some volcanologists write that it might occur, even from distant big quakes, if the volcano is already primed. Popocatepetl in 1994, in Mexico, might be an example.

Anyway, although seismologists I follow on Twitter said yesterday that these were probably on the subducting plate, i.e., not volcano related, the quakes were close to Raoul Island, which last erupted in 2006 but apparently is sound asleep now. That link is to the Smithsonian's GVP page, where any new bulletins are posted weekly.

GEONET is best for real-time alerts for any geologic events in the Kermedecs or other parts of that region. (Click "Volcanoes" in the menu to get to current info on Raoul, which is in the Kermedec Islands).)

Disclaimer: I am not saying any volcano in New Zealand or anywhere else is "about to blow." It's just an interesting geological situation, that's all, just one of many that come and go all the time on this wonderful planet.

Professionals are watching stuff, including all the volcanic activity lately, and as one of them tweeted (he's a petrologist who teaches at Dennison U and whose outreach blogging got me interested in volcanoes almost ten years ago):

 

[bjdeming]

Just out:

 

[bjdeming]

DART buoys caught a triple tsunami!