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PodClast - Episode 4: Sichuan Earthquake and Mars Phoenix Lander
Posted on Sunday, May 25, 2008 @ 10:37 am by Dave Schumaker
The fourth episode of the Goodschist PodClast is out today. This episode features Chris Town and myself. Due to technical difficulties, Chris and I decided to each record a separate segment of the PodClast, dealing with topics we were planning on discussing.
Show notes for Episode 4 are available on Chris’ webpage and relevant links will posted on the PodClast del.icio.us account.
Discussions this week feature a brief discussion on the Sichuan earthquake in China and the pending landing of the Mars Phoenix Lander.
Chris is always looking for new voices from the geoblogosphere to join in on the PodClast. If you’d like to participate next time, check out his information on joining the PodClast.
[Via GoodSchist]
On the Ground in China - Sichuan Earthquake Photos
Posted on Sunday, May 18, 2008 @ 5:22 pm by Dave Schumaker
There are quite a few sites sharing photos of the disaster across the internet. They include:
Cryptome.org - Listing photos by day: May 12 and 13, May 13 and 14, May 14, May 14 and 15, May 16, and May 16 and 17.
Warning: Some of these images are pretty powerful and may not be suitable for a work environment.
Shanghaiist, a Chinese blog on culture and entertainment (written in English), has had some great on-the-ground coverage of the earthquake and first hand accounts. Check that out for more information and video as well.
Source: AP, May 13, 2008.
Source: AP, May 13,2008.
Source: AP, May 14, 2008.
Source: AP, May 14, 2008.
Source: Getty Images.
The latest news from Chinese authorities say that 32,000 perished and 50,000 total are presumed dead.
Disseminating Information: Twitter vs. USGS on the Sichuan Earthquake
Posted on Thursday, May 15, 2008 @ 3:05 pm by Dave Schumaker
On Sunday evening, noted Bay Area tech blogger Robert Scoble, became one of the first people in the western hemisphere to find out about a large earthquake in China. He reposted a message he received on his Twitter account about the breaking news and within minutes, thousands of people around the world were aware that something had just happened.
Scoble’s Twitter message immediately after the Sichuan earthquake.
Later that evening, Scoble wrote a message on his blog, explaining how Twitter beat the USGS with information about the earthquake and sharing his amazement at learning about news as it happened on Twitter. Rory Cellan-Jones, a technology blogger for the BBC News, even went on to imply that this could mark Twitter’s “coming of age,” and establish its importance in disseminating information about major news events.
Does this really establish Twitter’s importance as a source of news? And how does this compare with the response time and information available from the USGS?
More after the jump. (more…)
Sichuan Quake Ruptured in 2 Stages
Posted on Thursday, May 15, 2008 @ 11:16 am by Dave Schumaker
According to Yuji Yagi, a seismologist at Tsukuba University in Japan, Monday’s Sichuan earthquake in China ruptured in 2 stages.
Yuji Yagi, a seismologist at Tsukuba University, said data show the 155-mile Longmenshan Fault tore in two sections, the first one ripping about seven yards, followed by a second one that sheared four yards.
Despite the two-stage quake, which he estimated lasted for about two minutes, it was the shallowness of the epicenter - only 6 miles - that contributed most to the temblor’s destructive power, he said.
“The damage was very severe because the quake’s epicenter was shallow, and the quake occurred in densely populated areas,” said Yagi.
The AP article doesn’t have many details, but it sounds like they are talking about a phenomenon that is similar to a “cascading earthquake,” which happens when rupture on one fault starts a chain reaction that causes a simultaneous rupture on a nearby fault, in essence, creating two earthquakes.
I thought we’ve talked about cascading earthquakes before on Geology News, but looking through the archives, it appears I have never posted about them here. I did briefly mention them on Metafilter back in 2006 (and referenced the same article above).
James Dolan of the University of Southern California in Los Angeles says that the work “reinforces our sense that earthquakes on one fault can and have triggered earthquakes on another.” He has dug trenches on the Cucamonga fault, showing that the fault breaks every 500 to 1,000 years, evidence that the USGS team used. The Sierra Madre ruptures every 5,000 to 10,000 and the San Jacinto every 100 to 300 years. An event cascading across all three would be the region’s “doomsday quake,” Dolan says. “If this ever happens, it’s incredibly infrequent.”
The doomsday event Ralph Archuletta, a seismologist at the University of California at Santa Barbara, imagines is the San Andreas Fault failing along with a big thrust fault, which might be hidden in the valley. But he agrees that the three faults acting alone, which are closer to metropolitan areas than the San Andreas, would be worrisome. “A 7.5-magnitude earthquake near a populated area is not insignificant — whether or not it implies a Denali-style event,” he says.
Severe Cracks in China’s Zipingpu Dam
Posted on Wednesday, May 14, 2008 @ 1:30 am by Dave Schumaker
Severe cracks were discovered in the Zipingpu Dam, located in China’s Sichuan province. The cracks were discovered after Monday’s earthquake. According to Chinese authorities, the “plant and associated buildings have collapsed and some are partly sunk.” The dam is locaed upriver from Duijiangyan City, which has a population of 630,000 people.
About 2,000 troops were sent to work on a dam near the epicenter of Monday’s earthquake, state-run media reported.
The Zipingpu dam, upriver from Dujiangyan in Sichuan province, was in “great danger,” the Xinhua news agency reported.
China.org said that the 7.9-magnitude earthquake had caused “severe cracks” in the dam.
The “plant and associated buildings have collapsed and some are partly sunk,” it said of the hydropower station.
The Ministry of Water Resources said that an irrigation system and Dujiangyan City — which has a population of about 630,000 — “would be swamped,” if major problems emerged at the dam, China.org said.
More information also available at Sky News.
Update: The dam is now reported to be stable and safe.
Update 2: Updated to a correct photo of the Zipingpu Dam, as the Internation Rivers website had an incorrect photo.