Earthquake
gregladen | March 1, 2016The Great San Francisco Earthquake(s)
On October 8th, 1865, the "Great San Francisco Earthquake" hit south of the city of San Francisco, magnitude 6.3.
On October 21st, 1868, the 'Great San Francisco Earthquake" hit near Haywards, east of the city, across the bay, magnitude 6.8.
On April 18th, 1906, the "Great San Francisco Earthquake" hit the Bay Area, magnitude 7.6.
The death tolls were unknown (but small), 30, and about 3,000, respectively.
Eighteen significant earthquakes happened after that (and five or so had happened between the first "great quakes") before February 9th, 1971, when…
gregladen | December 5, 2012I'm reading Disaster!: A History of Earthquakes, Floods, Plagues, and Other Catastrophes by John Withington, who also wrote about other disastrous things such as disasters specific to London. It is a couple of years old (and thus does not include the recent Japan earthquake and tsunami). This is more of a reference book than a sit-down-and-read-it book, and it lacks detailed presentation or critical analysis of sources, but if you want to know about a particular past major disaster or category of major disasters (volcanoes, floods, tsunamis, etc.) this is a good starting point. Reading…
gregladen | March 20, 2012The 7.6 7.4 magnitude earthquake struck 120 miles east of Acapulco. There are no details yet.
UPDATE: With a bit of time passing, it is starting to look like a lot of stuff got shook-up, but there was not a lot of significant damage anywhere.
gregladen | September 25, 2009Mount Rainier (14,410 ft) has lately attracted a small amount of attention because of what is considered by some an increase in seismic activity there, so I thought it might be nice to get a baseline description of this volcano for those of you interested in such things. For scientifically accurate information and interesting discussion on the mountain, keep an eye on Eruptions Blog.
Mount Rainier is a stratovolcano. This means that it is made up of strata of lava, tuff/tephra, ash, and so on that has been pushed out into a conical pattern. The lava from stratovolcanoes is usually…
gregladen | August 3, 2009Updated"
The USGS gives details of two earthquakes in the Baja region, Mexico.
At UTC 18:33 a 5.0 quake seems to have occurred at 28.931°N, 113.022°W, which is in the Gulf of California (a.k.a. Sea of Cortez) near and south of the island Angel de la Guarda. The second and larger quake, a 6.0 (preliminary) magnitude quake occurred at 29.568°N, 113.578°W is near the same island, but on the other side (north) of it.
It is fun to watch the news agencies get all confused. The only on the scene report we have is from about four hundred miles north-northeast, in San Diego, where the city…
gregladen | June 18, 2009I just got this massive continental plate sized press release from JPL. Below the fold.
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NASA Gives California's San Andreas, Other Faults a 3-D Close-up
When a swarm of hundreds of small to moderate earthquakes erupted beneath California's Salton Sea in March, sending spasms rumbling across the desert floor, it set off more than just seismometers. It also raised the eyebrows of quite a few concerned scientists. The reason: lurking underground, just a few kilometers to the northeast, lays a sleeping giant: the 160 kilometer (100 mile) long southern segment…
gregladen | February 10, 2009A quick note for those of you interested in mud volcanoes (and I know there are many of you). From an article titled "Earthquake Triggering of Mud Volcanoes" by Magna et al we learn that ...
Mud volcanoes sometimes erupt within days after nearby earthquakes. The number of such nearly coincident events is larger than would be expected by chance and the eruptions are thus assumed to be triggered by earthquakes. Here we compile observations of the response of mud volcanoes and other geologic systems (earthquakes, volcanoes, liquefaction, ground water, and geysers) to earthquakes. The…
gregladen | January 11, 2009Just as unexpectedly as when the last swarm started, and just as unexpectedly as when the last swarm stopped, there is a new swarm. Verifying my initial statement: At least at some levels, the experts don't have much of a clue about these things. Not their fault. It's just that there is not that much data and there has not been enough study.
After a few days of relative quiet, a new earthquake storm has started up in Yellowstone Natioal Park.
According to the Island Park News:
A modest swarm of earthquakes began in the northeast corner of the Yellowstone Caldera Friday, the Yellowstone…
gregladen | May 12, 2008It is estimated that between 3 and 5 thousand people have been killed by an earthquake in Beichuan County, Sichuan Province, China. That is about one in ten residence of this county.
ADDED: This number is increasing quickly.
In at least three cases, schools appear have collapsed trapping hundreds of students. About 900 students were trapped in a school in Dujiangyan city.
Teenagers buried beneath the rubble of the three-storey Juyuan Middle School building were struggling to break free, while others were crying out for help, state news agency Xinhua reported.
Parents were watching as…