Thank you! It is great to see some of the discussion happening in Japan right now - very useful for other places that might be thinking about the costs and benefits of similar protocols.
I fine quick report. My Japanese colleagues and I have conducted research on Japan's operational earthquake forecast (OEF) system and the M7.1 that occurred yesterday was the first to have triggered a mega-thrust earthquake advisory. In addition to a M7 class event, two other scenario events can prompt the JMA to issue either an advisory or a warning, a slow slip event that accelerates over a few hours to a few days may also cause an advisory to be issued. A M8 class earthquake, which would be a major and possibly tsunami-genic event in one segment of the Nankai Trough would be followed by a (Major Mega-Thrust) warning for all areas of the Nankai region which includes 29 prefectures and 707 municipal governments. Our project focused on local and prefectural governments and their level of planning for receipt of an advisory or a warning. We discovered that 85% of municipal governments in the Nankai region had plans for receipt of these notifications; however, many were minimal in scope with few provisions beyond setting up a disaster headquarters and mobilizing senior staff. We conducted a series of planning/training workshops, including one in Miyazaki City designed to enhance planning for an OEF from the JMA. The Miyazaki workshop was held on August 30, 2023 and was well attended by cities within Miyazaki Prefecture. We published a paper in Seismological Research Letters on our study which can be accessed at: https://doi.org/10.1785/0220230304
Hi James, thanks for that info, and for the link to the paper. It is fascinating to hear about efforts to support the earthquake advisories through this kind of outreach and interaction with local governments. I'm quite familiar with some social science studies of post-earthquake response, but not pre-earthquake preparations. Now that an advisory has been raised for the first time, are there plans to follow up and see what actions were actually taken at the municipal level? Cheers - Kyle
Thanks for your reply Kyle and yes, we have plans to follow up with the cities and prefectures that are part of the Nankai Region. One of our junior colleagues was conducting a tsunami drill in Miyazaki City when the earthquake occurred. The drill was quickly transformed into an actual evacuation. We also have a website for local emergency managers in the region. There is an English version (and of course a Japanese version) that includes the planning guidance document for OEF. Website is:https://nankai-sewi.dpri-info.com/en/index.html
Great reporting! One picky comment: "Figure 1: Map of felt ground shaking reports. Source: Japanese Meteorological Agency. Note that the intensities here are reported on the shindo intensity scale." That map is of JMA instrumental intensities, not shaking reports per se. Japan does not use traditional macroseismic intensities based on reported observations and/or observed damage, but rather, they compute JMA instrumental intensities from recordings at thousands of seismic stations.
Really enjoyed this article. I'm super interested what the response to the megaquake warning will be. I'm curious how they came up with the prediction that a megaquake might follow, or if it was a true shot in the dark similar to California's 5% likelihood number you mention.
Hello, really interesting and accessible post! Looking at the rupture history of the Nankai trench, the last full rupture was in 1707, with subsequent ruptures switching back between CD(E) and AB. This somewhat mirrors the pattern for earlier earthquake events, but not that closely. It also looks like that full ruptures are more likely to be proceeded by ruptures involving AB. Are we able to predict from any of this the probability that the next megaearthquake will involve a rupture along its entire length, or is it too hard to say? I ask these questions from a place of ignorance! Thanks
Dear Kyle and Judith, I'm a journalist at AFP news agency in Japan and I always appreciate receiving your timely and interesting, clearly written newsletters. We have quoted this one in our article today about Japan's 'megaquake advisory' https://today.rtl.lu/news/science-and-environment/a/2222019.html
Sure! Please delete my comment now that its job is done.
I look forward to reading your insights.
(I live in Yamaguchi, Yamaguchi prefecture and got a warning on my phone that the shaking was coming; but for some reason, our immediate are (or, at least, my house) did not experience any shaking despite our being in a Shindo 3 zone!)
Will do. I have upgraded your account to "paid" so you can access all of our archives, as a token of appreciation. (If you find any errors in those articles, please let me know!)
If I spot anything, I'll suggest a rewrite. I'm new to Substack, but will look for a profile that will let me contact you privately (rather than in public like this time :P ).
I just wrote to you through the direct messaging system on Substack; let me know if that doesn't go through. (Although public comments are also totally fine!)
The BBC stated that the current advisory will be in place for a week, but without a reference to where that information came from.
This is K.Otani in Japan (random common resident in Tokyo)
I could not find an English article explains why the advisory will be in place for a week. (it is a combination of possibility and social issues)
This article explains well. Sorry about Japanese and paywall.
https://digital.asahi.com/articles/ASS883GJ7S88PLBJ006M.html
Thank you! It is great to see some of the discussion happening in Japan right now - very useful for other places that might be thinking about the costs and benefits of similar protocols.
I fine quick report. My Japanese colleagues and I have conducted research on Japan's operational earthquake forecast (OEF) system and the M7.1 that occurred yesterday was the first to have triggered a mega-thrust earthquake advisory. In addition to a M7 class event, two other scenario events can prompt the JMA to issue either an advisory or a warning, a slow slip event that accelerates over a few hours to a few days may also cause an advisory to be issued. A M8 class earthquake, which would be a major and possibly tsunami-genic event in one segment of the Nankai Trough would be followed by a (Major Mega-Thrust) warning for all areas of the Nankai region which includes 29 prefectures and 707 municipal governments. Our project focused on local and prefectural governments and their level of planning for receipt of an advisory or a warning. We discovered that 85% of municipal governments in the Nankai region had plans for receipt of these notifications; however, many were minimal in scope with few provisions beyond setting up a disaster headquarters and mobilizing senior staff. We conducted a series of planning/training workshops, including one in Miyazaki City designed to enhance planning for an OEF from the JMA. The Miyazaki workshop was held on August 30, 2023 and was well attended by cities within Miyazaki Prefecture. We published a paper in Seismological Research Letters on our study which can be accessed at: https://doi.org/10.1785/0220230304
Hi James, thanks for that info, and for the link to the paper. It is fascinating to hear about efforts to support the earthquake advisories through this kind of outreach and interaction with local governments. I'm quite familiar with some social science studies of post-earthquake response, but not pre-earthquake preparations. Now that an advisory has been raised for the first time, are there plans to follow up and see what actions were actually taken at the municipal level? Cheers - Kyle
Thanks for your reply Kyle and yes, we have plans to follow up with the cities and prefectures that are part of the Nankai Region. One of our junior colleagues was conducting a tsunami drill in Miyazaki City when the earthquake occurred. The drill was quickly transformed into an actual evacuation. We also have a website for local emergency managers in the region. There is an English version (and of course a Japanese version) that includes the planning guidance document for OEF. Website is:https://nankai-sewi.dpri-info.com/en/index.html
Great reporting! One picky comment: "Figure 1: Map of felt ground shaking reports. Source: Japanese Meteorological Agency. Note that the intensities here are reported on the shindo intensity scale." That map is of JMA instrumental intensities, not shaking reports per se. Japan does not use traditional macroseismic intensities based on reported observations and/or observed damage, but rather, they compute JMA instrumental intensities from recordings at thousands of seismic stations.
Thanks!
I have edited the caption following your comment. Thanks once again for your expertise - it is very helpful!
Really enjoyed this article. I'm super interested what the response to the megaquake warning will be. I'm curious how they came up with the prediction that a megaquake might follow, or if it was a true shot in the dark similar to California's 5% likelihood number you mention.
Hello, really interesting and accessible post! Looking at the rupture history of the Nankai trench, the last full rupture was in 1707, with subsequent ruptures switching back between CD(E) and AB. This somewhat mirrors the pattern for earlier earthquake events, but not that closely. It also looks like that full ruptures are more likely to be proceeded by ruptures involving AB. Are we able to predict from any of this the probability that the next megaearthquake will involve a rupture along its entire length, or is it too hard to say? I ask these questions from a place of ignorance! Thanks
Dear Kyle and Judith, I'm a journalist at AFP news agency in Japan and I always appreciate receiving your timely and interesting, clearly written newsletters. We have quoted this one in our article today about Japan's 'megaquake advisory' https://today.rtl.lu/news/science-and-environment/a/2222019.html
Thank you for letting us know!
Oh no! You are exactly right. I have deleted that line. Thanks so much for pointing that out.
Sure! Please delete my comment now that its job is done.
I look forward to reading your insights.
(I live in Yamaguchi, Yamaguchi prefecture and got a warning on my phone that the shaking was coming; but for some reason, our immediate are (or, at least, my house) did not experience any shaking despite our being in a Shindo 3 zone!)
Will do. I have upgraded your account to "paid" so you can access all of our archives, as a token of appreciation. (If you find any errors in those articles, please let me know!)
Wow, thanks!
If I spot anything, I'll suggest a rewrite. I'm new to Substack, but will look for a profile that will let me contact you privately (rather than in public like this time :P ).
I just wrote to you through the direct messaging system on Substack; let me know if that doesn't go through. (Although public comments are also totally fine!)