Western Japan New Year Earthquake

[WesL]

7.4 earthquake is how residents of Western Japan experienced on Jan 1. A tsunami warning was issued along with evacuation orders.

 

[JBishopwx]

 

[bjdeming]

JMA tsunami page with graphic. What's mindboggling is that there are waves even though the focus was not offshore, per this retired seismologist (Twitter will translate). Per Guardian's live coverage, Russia and South Korea are under warning, too.

Here is a seismologist account I follow. Note, too, her tweet that some of the videos online are from other events.

 

[bjdeming]

This is the retired seismologist again. He says"It's kind of amazing," which is true. Graphic in tweet shows hypocenters that occurred from 1900 on the 31st to 1846 on the 1st.

Link doesn't autotranslate but your browser might do it.

 

[bjdeming]

 

[bjdeming]

Gosh.

"As of 1/1 18:57 JST: USGS ( https://earthquake.usgs.gov/earthquakes/eventpage/us6000m0xl/finite-fault… ) is analyzing slippage in a long and narrow area from the west coast of the Noto Peninsula to the waters around Sado. The aftershock area ( https://jma.go.jp/bosai/map.html#9/37.444/137.304/&contents=hypo… ) is equally long."

 

[bjdeming]

This one looks tricky -- not clear-cut like the MUCH larger 2011 megathrust quake was.

(Layperson speculation) It seems from the little bit I've seen on geotwitter that the overall event continues (M5-ish aftershocks are ongoing as the stress field adjusts) and that multiple faults are involved.

Behind it all might be this (/layperson speculation): per this geophysicist (and Twitter translation), "...it appears that an active submarine fault on the northern edge of the Noto Peninsula has moved."



That explains why different depths are given on various earthquake reports online. But read all the other tweets, too.

 

[bjdeming]

Epicenter distribution through about an hour ago (currently 2028 local time):

 

[bjdeming]

"Major earthquakes to date. According to the Japan Meteorological Agency epicenter distribution. As far as this data is concerned, it appears that earthquakes began to occur on the Shiga Town side at the southwest end of the epicenter area fairly soon after the main shock, and on the northeast offshore side a while after the main shock. black writing"

 

[UncleJuJu98]

Just saw this on the news and It brang back memories of the awful earthquake and tsunami back in 2011

 

[bjdeming]

It's cold, it's dark, people are probably trapped, and tens of thousands are without power. Also, some of the Japanese tweeters note that many holiday makers from Tokyo and Osaka have swelled the peninsula population -- and they can't leave; the transportation system is down (landslides, infrastructure damage, etc.)

 

[bjdeming]

The risk of more tsunamigenic events isn't off the table yet (saw reports just now of a 26-inch wave at South Korea):

"Regarding earthquakes that have occurred in the past, you may think that collapses are more scary than tsunamis, but the epicenter extends to the offshore, and if that moves next, it will be another tsunami, so in that sense, we should be on guard against tsunamis for a while. It's probably best to do that."

 

[bjdeming]

"Please stay in a safe place and help each other survive the night."

 

[TH2002]

Some of the images that have come out of the Ishikawa Prefecture are pure nightmare fuel. It reminds me of the movie "Volcano", only scarier because this is real life.

 

[bjdeming]

A measure of the impacts is that the disaster began at around 4:30 p.m. yesterday, it's 11 a.m. there now, and the Japan Times, whose website crashed last night, could only report this an hour ago:

Authorities in Japan on Tuesday were rushing to assess the damage the day after a powerful earthquake left at least 13 dead, led to the collapse of multiple buildings, sparked a large-scale fire in a popular tourist area and triggered a tsunami warning for the length of the nation’s west coast.

A basic graphic showing why this is so different from the subduction-zone quakes we usually associate with Japan:




Indirectly, it is due to subduction, in the sense that the Sea of Japan opened up long ago due to back-arc spreading, but it is a much more complex tectonic scenario.

 

[warneagle]

Some of the images that have come out of the Ishikawa Prefecture are pure nightmare fuel. It reminds me of the movie "Volcano", only scarier because this is real life.

Reminds me from the images of the Okushiri earthquake in 1993 (although that tsunami was much worse).

 

[bjdeming]

Not official, but both poster and the Twitter source that reposted it on my feed are reliable:



Here is an official technical report, autotranslated.

 

[bjdeming]

JMA's latest report (autotranslated), with Wikipedia article on their earthquake scale.

The tsunami warning was lifted a couple of hours ago but sea movements are still unpredictable.

Also, more 7-pointers could happen in the next few days.

 

[Tennie]

And now even more bad news:

While landing, a Japan Airlines passenger plane apparently collided with a Japan Coast Guard aircraft that was reportedly loaded with aid for the earthquake-stricken area. The passengers and crew managed to evacuate, but Japan's transport minister reported five deaths on the Coast Guard plane.

Here's some news coverage about it from the BBC:



(When it rains, it pours...)

 

[bjdeming]

Okay, if I've got everything right from geotweets (in Japanese), what we are looking at here is not the typical withdrawal of water before a seismicity-generated tsunami comes in; it is the peninsula in this region actually rising "x" meters (have read various values; it apparently varied by location) and moving about 3 meters (apparent consensus) westward.

Here is a related view (the Spanish is from a Mexican geologist; ? who the Japanese tweeter is):



Incredible, indeed!

One authoritative tweet reported that a GNSS station, near the city where that big fire happened, moved 4 feet westward and also rose -- but my browser crashed and I can't find it again in among all the Japanese geotweets, so the height is ?

The peninsula apparently broke with the 7-pointer and then fault movement took place on both sides of that point. AFAIK that is unusual.

The human news is still appalling, and the authorities are still warning that more tremors could happen.

PS: That channel's live cams are back up; I haven't checked into them yet because I need to take a break from foreign languages for a bit.

PPS: This link will take you to a page (in Japanese) that shows disaster operations, damage, etc. Google Translate handles the menu, but the map links won't work. Just reduce the menu and follow what's on the map.

PPS: And here is a fact-checking site for information (autotranslated but ? if it will carry through a click). This URL to the Noto disaster link might work better but, naturally, everything is losding slowly right now.