While the Japan earthquake has dominated the media obviously, some other news came up in geoscience. A researcher team lead by Ludovic Ferrierè who works at the Natural History Museum in Vienna claims to have proven the first impact crater in central Africa. The Luizi structure in the Democratic Republic of Congo was described in 1919 by a German study, but has not been confirmed as an impact crater for decades. Ferrierè and his team now found shatter cones and shocked quartzes, strongly pointing to an impact. The crater has a diameter of 17 km and a 350 m high rim, which led the scientists to assume a meteor of 1 km diameter and a velocity of ~20,000 m/s. more
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. more
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. more
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. more
