On top of the 6.8 (or whatever it was) quake on the east coast a few hours ago, I just got an alert of a 7.2 in the same location. We're going from really strong to, "Shit, I'm going to die if I don't get out of this structure" strength.

It looks like it's been revised to a 6.9, which I believe is still stronger than the one earlier, or the strongest yet so far. To have a 6+ followed by a 6.9 would be very frightening and unusual.

It's a full-on earthquake swarm. Most epicentres seem to be just west of the coastal range (creeping north?) - so it's in the Rift Valley. There's a reason why they call it the Rift Valley, making it hard to know where the peak is. That fault line has got an 8+ in it - hopefully this will be well short of that.

Started watching it on CWB this morning - you could see the earthquakes going off in real time - which is impressive tech-wise.

Here's the live CWB link
https://www.cwb.gov.tw/V8/E/E/index.html

They say Sep is earthquake season - due to the change from hot to cooler. Apparently that doesn't make sense - weather can't affect earthquakes - but there was 921, and these ones, and now i see a 7.6 in Mexico, which is the anniversary of two other big earthquakes there in 1985 & 2017 ...

This is interesting - as close as i've seen to state-announced earthquake prediction

(Taiwan News) — The effort to monitor fault activities in Taiwan will be centered on the central-southern region of western Taiwan, an official of the Central Weather Bureau (CWB) said, as experts caution about unreleased seismic energy in the west.

Chen Kuo-chang (陳國昌), director of the CWB Seismological Center, said on Tuesday (Sept. 20) that the region of Chiayi and Tainan is strewn with many fault lines. Around ten fault lines are located in densely-populated areas while four are “of particular concern,”.

The official would not disclose details of the faults requiring vigorous monitoring to avoid sending the public into a panic.

That's exactly the conundrum we talked about. The balance between accuracy & causing panic.

The view was echoed by Wang Chung-ho (汪中和), a fellow researcher at Academia Sinica’s Institute of Earth Sciences, who voiced concern about relatively fewer quakes in western Taiwan.

According to Wang, the number of quakes being felt has seen a remarkable decrease since September of 2018, and the build-up of energy can be alarming. The likelihood of seismic hazards has been raised in the western region due to energy that has failed to be unleashed, he cautioned.

The researcher also pointed out an unusual phenomenon that he believes may be a precursor to a large earthquake, wrote the Environmental Information Center. The drop in groundwater levels in Taitung was detected in June this year, while similar signs were recorded in Changhua, Yunlin, and Nantou prior to the devastating Jiji quake that hit central Taiwan on Sept. 21 of 1999.

That's Taiwan's two top experts warning of a potential big-one coming for central-south west Taiwan.

It's not entirely clear if they've already observed a drop in water-levels in the central-south west - did he point it out as something to watch for ... or something that has already happened ...?

That it's been narrowed down to four fault-lines is noteworthy - quite specific.

The map gives an idea of where it's expected. Looks like Chiayi area again. That's where the big 7+'s are possible.

The researcher also pointed out an unusual phenomenon that he believes may be a precursor to a large earthquake, wrote the Environmental Information Center. The drop in groundwater levels in Taitung was detected in June this year, while similar signs were recorded in Changhua, Yunlin, and Nantou prior to the devastating Jiji quake that hit central Taiwan on Sept. 21 of 1999.
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It's not entirely clear if they've already observed a drop in water-levels in the central-south west - did he point it out as something to watch for ... or something that has already happened ...?

Very interesting. I see what you mean. They say the observed drop in groundwater was in Taitung, which normally isn't considered souch-central Taiwan unless you're referring to the far western parts of the county, and even then it's a stretch.

Perhaps that's just the location of the most recent relevant measurements made. I do know that all the fish ponds in southern Taiwan are responsible for draining the groundwater, and that raises the question of whether the overuse of groundwater for aquaculture could contribute to earthquakes.

Or maybe they discount groundwater measurements in southern Taiwan because they know they are artificially affected by aquaculture while those in Taitung county would more closely reflect natural changes.

Does seem they're predicting a big-one - like any tick of the clock ...

With the 'rigorous monitoring' - wonder if that means the prediction will become more refined?

Had a quick review of 921 - didn't see any mention of precursor-shocks such as what we saw in the SE recently. I think 921 came pretty much out of the blue, right?

It came out of the blue for us, but we were down south. But, yeah, I don't remember any activity leading up to that. I think it just hit.

It's still bubbling away in the SE, but nothing west of the central range. 12 quakes since yesterday - the biggest being 4.7M - which is definitely enough to keep you feeling jittery. In fact it's an uptick after a slight lull.

By the way, Brian & Minshu's bar was badly damaged by the first big one on Saturday night when some of the old brick-work from Sugar Factory crumbled. Given it happened at 9.45pm on a Saturday night - that's not good timing for a bar - but luckily no-one was injured. Min-shu said it was like a disaster movie - crashing, clouds of dust, people screaming, running, falling over ...

Really sorry for B&M - it's one thing to say 'lucky no-one was hurt' but it's not nice having your business smashed, trying to pick up the pieces. Not sure they will be able to continue at that location.

That's too bad. I thought about them after those earthquakes, but of course I wondered how much beer they lost! I imagined lots of broken bottles and such. It didn't occur to me that the building might have partially collapsed, but in fact that's been my experience -- un-reinforced brick structures do not do well in earthquakes.

In the big San Francisco earthquake of 1984(?), brick buildings were among the casualties, along with anything built on landfill. Apparently landfill turns to mush in an earthquake.

Our current house is on landfill, my school is on landfill. Come to think of it I spend most of every day on landfill! When I visually strip away the landfill areas in this region, I see steep hills rising right out of the bay.

That's too bad. I thought about them after those earthquakes, but of course I wondered how much beer they lost! I imagined lots of broken bottles and such. It didn't occur to me that the building might have partially collapsed, but in fact that's been my experience -- un-reinforced brick structures do not do well in earthquakes.

In fact, i think most of the beer survived! But it was that brickwork which must have been ready to go.

Although it was a 6.4, which is very decent, it did occur in the Rift Valley. I think mountain ranges, in this case the coastal range, do provide some protection if they're between you and the epicentre. Apart from their bar, it seems Dulan was relatively ok.

The one we had in 2016 was smaller, but the epicentre was pretty much right under my house. That seemed to cause more general damage in the area - though didn't bring the bar's wall down - so go figure ... Guess it's one of those accumulation things.

Sugar Factory is a heritage-listed building, which further complicates getting repairs done. You'd also wonder if that huge chimney right next to the bar could topple.

Two more 4M+ for the east coast overnight. These ones do seem to be east of the coastal range - both very shallow.

Meanwhile, one small earthquake on the central range, which is right where CWB is predicting a potential 'big-one'. If there's a sign of increased activity there then head for the hills - actually head away from the hills.

https://www.cwb.gov.tw/V8/E/E/index.html

This has been a prolonged period of activity for Taitung, going months now.

Interesting earthquake today near Kenting - not sure i've ever seen an earthquake there before. Dan would know better, having lived in Pingtung.

There was a large quake in that area, offshore a bit, back in 2006 or 7 that cut an undersea cable that supplied Internet to HK. I remember it well because my school at the time had a visitor from HK and he was genuinely angry that a quake in Taiwan knocked out there Internet for over two weeks while it didn't affect us at all! It was large though. We definitely felt it. Six point something.

There's been unusual activity in Japan as well. We had a 6.1 a few days ago offshore, but it was very deep, then a few minutes later we had two 4.+ quakes far north, hundreds of K away from the first one. Very odd. The Japan weather site is so poorly designed though that I can't easily find those records, and it was just 3-4 days ago.