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Significant Earthquake and Tsunami Events

Sixty-one (not sixty) years ago today:

 
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This is a good science source on the Myanmar-Thailand M7.7 quake:

 
Over 1600 deaths in Myanmar, and they're still trying to reach trapped people by hand.

And in Bangkok on the 28th, from one of the aftershocks --



Some knowledgeable people tweet that acceleration in the main shock -- the sideways force a structure experiences -- exceeded 1 (the downward force of gravity on the structure). They mention possible geophysical reasons for this unusual intensity, but I couldn't follow them.
 
The geologist who reposted that tweet wrote (X translation): "This is Park Origin Thonglor, a luxury apartment complex in the center of #Bangkok , #Tailandia with just over 1,100 apartments spread across three towers connected by skylights. The tallest tower stands 229m tall and was opened in 2022.

"It's worth noting that the epicenter of the 7.7 MW earthquake that caused the earthquake observed in the video originated in the center of #Myanmar , just over 1,000 km to the northwest. While the oscillation may seem alarming at first glance, it's a natural response to the epicenter's distance. It demonstrates the importance of considering seismic activity in the design of high-rise structures, especially in earthquake-prone regions."

Thread continued: "The video shows that each tower at Park Origin Thonglor oscillated at a different frequency during the earthquake. This difference in oscillation frequency caused relative movement between the towers, which could have tested the structural integrity of the bridges connecting them.While the architectural design is bold, the region's seismic activity raises questions about the viability of such structures."
 
For geonerds and curious folks -- a USGS ARCGIS story map on the Myanmar quake.
 
This is so cool!

 
X translation: "It was a night nine years ago that the Kumamoto earthquake struck. Two earthquakes of "magnitude 7" struck the area, causing houses to collapse one after another, and the number of "disaster-related deaths" was more than four times the number of direct deaths. It also became an opportunity to reconsider the use of the word "aftershock." This disaster highlighted the threat of shallow earthquakes and left many lessons."



There is a supervolcano nearby (or large caldera system, as they're sometimes called), and I was surprised to learn while researching a post on it that the magma chamber might have stopped the earthquake fault rupture and reduced the aftershocks near the volcano. (Source)
 
None of them have been major yet, but the swarm in Japan's Tokara Islands has passed a thousand felt events, with an M5.5 today. News reports say that the stress is getting to residents.

Per this NHK story (Japanese), Japan Meteorological Agency (JMA) is adjusting its weather advisories for the area to take shaking effects on the ground into account, which is a very good idea:

...
The Japan Meteorological Agency has decided to lower the standards for issuing heavy rain advisories, heavy rain warnings, and landslide warnings to 70% of normal for the time being, as the ground in Toshima Village is likely to be loose and the risk of landslides is higher than usual.

In addition, in areas where the shaking was strong, the agency is urging people to pay close attention to future seismic activity and rainfall patterns, such as the collapse of houses and landslides, and to be on the lookout for earthquakes with a maximum seismic intensity of about 6-, as there is no end in sight to the seismic activity.

Meanwhile, with regard to the relationship between the recent earthquake and the spreading rumors of a major earthquake in Japan, the Japan Meteorological Agency has stated that earthquakes cannot be predicted with current science and technology, and that they are hoaxes.
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Two notes:

  1. The values given in that quote are for shaking intensity, not magnitude; there have been some 5-pointers, though, including an M5.5 today.
  2. That last paragraph references a rumor (Japanese) that a major earthquake and severe tsunami will hit Japan on July 5th; apparently someone saw it in a dream. Sigh. This probably is not helping soothe the jangled nerves of Tokara Island residents, though there is no report that any of them have bought into that fantasy.
I don't know if it's volcanic, tectonic, or both but decided to blog it and see what happens (if anything -- seismic swarms have happened in this area before, just not so many quakes or so many felt ones).
 
Was looking at the JTWC website to produce an update post on the Global Tropical Cyclones thread I made back in December 2024, and I saw this:
IMG_4788.jpeg
That’s gotta be the first time I’ve seen this in red light before. Usually it’s green.
 
Haven't seen any maps. But this is from the latest PTWC update.


WEAK51 PAAQ 162113
TSUAK1

BULLETIN
Public Tsunami Message Number 2
NWS National Tsunami Warning Center Palmer AK
113 PM AKDT Wed Jul 16 2025

UPDATES
-------
* A tsunami has been confirmed and some impacts are expected
* Revised magnitude


...THE TSUNAMI WARNING REMAINS IN EFFECT...


Tsunami Warning in Effect for;

* SOUTH ALASKA AND THE ALASKA PENINSULA, Pacific coasts from
Kennedy Entrance, Alaska (40 miles SW of Homer) to Unimak
Pass, Alaska (80 miles NE of Unalaska)


For other US and Canadian Pacific coasts in North America,
there is no tsunami threat.
 
TornadoFan said:
Haven't seen any maps. But this is from the latest PTWC update.


WEAK51 PAAQ 162113
TSUAK1

BULLETIN
Public Tsunami Message Number 2
NWS National Tsunami Warning Center Palmer AK
113 PM AKDT Wed Jul 16 2025

UPDATES
-------
* A tsunami has been confirmed and some impacts are expected
* Revised magnitude


...THE TSUNAMI WARNING REMAINS IN EFFECT...


Tsunami Warning in Effect for;

* SOUTH ALASKA AND THE ALASKA PENINSULA, Pacific coasts from
Kennedy Entrance, Alaska (40 miles SW of Homer) to Unimak
Pass, Alaska (80 miles NE of Unalaska)


For other US and Canadian Pacific coasts in North America,
there is no tsunami threat.
Click to expand...
A magnitude 7.2 earthquake is a decently strong earthquake, but not the strongest. It is among the strongest though.

I hope everyone along those warned shores stays safe.
 
Atlantic said:
I hope everyone along those warned shores stays safe.
Click to expand...

Per the Earthquake Center:

The National Tsunami Warning Center issued a tsunami warning immediately after the earthquake, but downgraded it about an hour later to an advisory. Several communities issued tsunami evacuations, including Sand Point, King Cove, Kodiak, Old Harbor, Homer, Seward, and Unalaska. While no tsunami was observed for this event, the issued tsunami warning helps communities nearby quickly respond with very little time to evacuate. If an impactful wave had been generated during this event, those communities closest to the epicenter would have had minutes to evacuate.
Click to expand...
 
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