Dr. Melanie Michalak, Geology Chair at Cal Poly Humboldt, where I taught, talks about the basics of earthquake-generated tsunamis, like yesterday’s.

https://www.wbur.org/hereandno...

 geoff_morphini wrote:

Looks like a classic megathrust number. Given its size and location, the tsunami appears to be pretty mild. 

(Not to be underestimated though. There were two deaths in Peru on the other side of the Pacific from the Hunga Tonga eruption IIRC from guys caught unawares and this tsunami is definitely bigger than that.)

The Redwood Coast Tsunami Working Group (RCTWG) is one of the foremost community tsunami, and earthquake, preparedness and information groups in the US. Dr. Lori Dengler, a colleague, is a world expert in the topic. If you want to stay abreast of what’s going on in real time I suggest you go here.

https://www.facebook.com/share...

 Steely_D wrote:


Now upgraded 8.8, which is a sizable logarithmic step up!

 Steve wrote:

Upgraded to 8.7

And if you’re in Hawaii, GET TO HIGHER GROUND
 https://tsunami.gov

If you're near a Pacific Coastline, it might be a good idea to get on your favorite search engine to look for 'Tsunami Warning."

very tragic, particularly when people should now know to get the hell away from the water after a strong quake. Not that everyone could, of course after a M7.5 quake, but still.

"long, strong: get gone"

Unfortunately the Indonesian authorities revoked the tsunami warning on the basis of distant tidal gauge, ignoring potential local effects. (edit: apparently the warning was only revoked after the waves had already struck)

Whether that had any impact or not I don't know. I imagine the infrastructure was anyway not working so well directly after the quake.
Also, looking at today's aerial footage, it appears the land where the tsunami was most devastating has actually sunk a meter or two, making it susceptible to inrushing water.  That sort of thing is not going to show up on a mid-ocean tsunami gauge.

From the Guardian:

However, Cummins and Adam Switzer, the chairman of the Asian school of environment at Nanyang Technological University in Singapore, were in agreement that the disaster was a failure not of technology but of education. Unlike the 2004 tsunami that devastated south Asia, this wave was not was prompted by an earthquake hundreds of miles out to sea. Instead it was a localised tsunami resulting from an earthquake close to the coast. It has been estimated that the tsunami waves hit Palu only 30 minutes after the quake. “For the people on the beach and in the city, the earthquake should have been the early warning,” Switzer said.

Indonesia earthquake and tsunami death toll surpasses 830