{"id":9232,"date":"2020-01-12T11:43:25","date_gmt":"2020-01-12T19:43:25","guid":{"rendered":"http:\/\/earthjay.com\/?p=9232"},"modified":"2024-11-12T01:59:10","modified_gmt":"2024-11-12T01:59:10","slug":"earthquake-report-puerto-rico","status":"publish","type":"post","link":"https:\/\/earthjay.com\/?p=9232","title":{"rendered":"Earthquake Report: Puerto Rico!"},"content":{"rendered":"

Welcome to the next decade of the 21st century. We may look back a decade to review the second most deadly earthquake in the 21st century, from the magnitude M 7.0 Haiti Earthquake on 12 Jan 2010. I put together an overview of this event sequence here<\/a>.<\/p>\n

Since late December, southwestern Puerto Rico has seen a sequence of smaller (M3-5) earthquakes, culminating with the 29 Dec 2019 M 5 which later turned out to be a foreshock (there was also a M 4.7 that was a foreshock to the M5). Then on 6 Jan, there was a M 5.8, which was now the mainshock. Then, on the following day, there was the real mainshock, the M 6.4. Lots of other earthquakes too. The largest aftershock was the M 5.9 on 11 Jan. Below I include some comparisons for the M 6.4 and M 5.9 quakes.<\/p>\n

Here is a plot showing the cumulative energy release from this sequence. I used the USGS NEIC earthquake catalog for events M\u22650. Time is on the horizontal axis and energy release (in joules) on the vertical axis. For every earthquake, the plot steps up relative to the energy released by that quake.<\/p>\n


\n\"\"<\/a><\/p>\n

These earthquakes in Puerto Rico have been deadly and damaging. Many structures there are constructed with soft stories on the ground level (the buildings are uplifted to mitigate hurricane flood hazards). Unfortunately, these soft story structures don’t perform well when subjected to earthquake shaking. Thus, there have been many structure collapses. Luckily, there have been only a few deaths. While we may all agree that having no deaths is best, there could have been more.<\/p>\n

The M 6.4 even generated a small tsunami. This was localized and was observed clearly on only one tide gage (The Magueyes Island gage).<\/p>\n

Here is the tsunami record, along with a map showing the location of the tide gage in southwestern Puerto Rico. These data are from a site that is my “go-to” website for looking for tsunami in tide gage data<\/a>. I generally look here first.<\/p>\n


\n\"\"<\/a><\/p>\n

USGS Earthquake Event Pages<\/font><\/h2>\n