Liquefaction in Tokyo Central Park

Thanks to Alessandro I came across this incredible video of liquefaction occuring in the Tokyo Central Park during the M9.0 Japan earthquake. We can see a lot of very interesting features. First, cracks are opening, perfectly visible on the paved road and the cobble. Then we see the differential moving along those cracks, they are widening and narrowing and there’s vertical movement as well. Soon, the first ruptures appear in the meadows, despite the soft sediment there. Continue reading “Liquefaction in Tokyo Central Park”

Japan EQ & Tsunami: Environmental Effects

The Japan M9.0 earthquake and the following tsunami are well documented by videos, photographs, sea-level measurements, seismograms etc. But how do we recognize such huge events if they happened some thousands of years ago? If there’s no historical report we would use earthquake environmental effects (EEE) for characterizing the earthquake and paleoseismicity. Let’s look what would be left from a 5000 year old earthquake and tsunami. Continue reading “Japan EQ & Tsunami: Environmental Effects”

Mw9.0 earthquake hits Japan, causes Tsunami (updated – 3)

An earthquake with a magnitude of Mw9.0 has occured 130 km east of Honshu, Japan in a depth of ~25 km. This had been the fourth or fifth strongest earthquake to be recorded by instrumental seismology. The quake caused significant destruction to the Honshu Island and triggered a tsunami that  destroyed a number of harbours. In some places (Sendai), tsunami heights were reported to exceed 10 m. A tsunami warning has been released for wide parts of the Pacific, but in Hawaii only 1 m was observed, therefore the warnings for the US West Coast have been lowered. Continue reading “Mw9.0 earthquake hits Japan, causes Tsunami (updated – 3)”

What’s up? The Friday links (8)

The Christchurch earthquake was the main topic of the Geoblogosphere this week. A great analysis on the effects was provided by Dave Petley in his Landslide Blog. Highly Allochthonous reasoned on seismic lensing, Ontario Geofish posted a lot on building security, and countless news sites came up with photos and reports. Frank Taylor, who hosted the GoogleEarthBlog before he left for a sailing trip around the world, was in Christchurch next to the Cathedral when the quake happened. On his Tahina Expedition website he reports on his experiences.

Continue reading “What’s up? The Friday links (8)”

Why was the Christchurch earthquake so devastating?

A M6.3 earthquake hit Christchurch, New Zealand on 22 February (21 Feb in UTC), leaving at least 75 people dead and hundreds injured or missing. Hundreds of houses were destroyed, including the Christchurch Cathedral, and damages will probably sum up to some billion dollars. On 4 September 2010 (3 Sept in UTC), a M7.0 event struck Christchurch, but then no one was killed. So: what’s the difference between the two events?

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What’s up? The Friday links (6)

Today on Friday, 11 February, a magnitude 7.0 earthquake occurred offshore in Chile near Concepcion at  36.5° S and 73° W in a depth of 28km. The MMI at the nearby large cities was reported by the USGS with V.

Update: The magnitude was corrected to 6.8. The earthquake was followed one hour later by a further event with a magnitude of 5.3 and 4 hours later again by a more shallow 6.3.
Continue reading “What’s up? The Friday links (6)”

What’s up? The Friday links (4)

The California Geological Survey provides a great online-tool for geoscientist: A fault map of California (Alquist-Priolo-Fault-Zone with all datasets available in PDF and GIS format for free! Start here.

A volunteer panel that assesses earthquake risks in Utah said it examined nearly 130 school buildings in the state and found more than half fail to meet federal earthquake safety guidelines. Bad news from here.

Continue reading “What’s up? The Friday links (4)”