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06-04-2015, 08:01 PM
The actual press release is at:
http://news.agu.org/press-release/little...alifornia/
due to my basic incoherence (?), there are a couple of problems in that. The shallow shelf around the mainland is extremely narrow compared to passive margins like the offshore east USA coast. But, the area of basins and ridges is exceptionally wide (200 km) offshore southern California and northern Baja.
The M8 quake possibility I mentioned was just logic, and it was not supposed to be a suggestion that there could be M8 quakes on the faults Legg studied. Instead, logically there could be very large quakes on the underlying flatter faults.
here is part of the story. Note that the parts that are not in quotes I did not say, but instead the author summarized whatever it is that I did say:
****************************
“Such large faults could even have the potential of a magnitude 8 quake,” said geologist Christopher Sorlien of the University of California at Santa Barbara, who is not a co-author on the new paper.
“This continental shelf off California is not like other continental shelves – like in the Eastern U.S.,” said Sorlien. Whereas most continental shelves are about twice as wide and inactive, like that off the U.S. Atlantic coast, the California continental shelf is very narrow and is dominated by active faults and tectonics. In fact, it’s unlike most continental shelves in the world, he said. It’s also one of the least well mapped and understood. “It’s essentially terra incognita.”
“This is one of the only parts of the continental shelf of the 48 contiguous states that didn’t have complete … high-resolution bathymetry years ago,” Sorlien said. And that’s why getting a better handle on the hazards posed by the Borderland’s undersea faults has been long in coming and slow to catch on, even among earth scientists, he said.
Chris
http://news.agu.org/press-release/little...alifornia/
due to my basic incoherence (?), there are a couple of problems in that. The shallow shelf around the mainland is extremely narrow compared to passive margins like the offshore east USA coast. But, the area of basins and ridges is exceptionally wide (200 km) offshore southern California and northern Baja.
The M8 quake possibility I mentioned was just logic, and it was not supposed to be a suggestion that there could be M8 quakes on the faults Legg studied. Instead, logically there could be very large quakes on the underlying flatter faults.
here is part of the story. Note that the parts that are not in quotes I did not say, but instead the author summarized whatever it is that I did say:
****************************
“Such large faults could even have the potential of a magnitude 8 quake,” said geologist Christopher Sorlien of the University of California at Santa Barbara, who is not a co-author on the new paper.
“This continental shelf off California is not like other continental shelves – like in the Eastern U.S.,” said Sorlien. Whereas most continental shelves are about twice as wide and inactive, like that off the U.S. Atlantic coast, the California continental shelf is very narrow and is dominated by active faults and tectonics. In fact, it’s unlike most continental shelves in the world, he said. It’s also one of the least well mapped and understood. “It’s essentially terra incognita.”
“This is one of the only parts of the continental shelf of the 48 contiguous states that didn’t have complete … high-resolution bathymetry years ago,” Sorlien said. And that’s why getting a better handle on the hazards posed by the Borderland’s undersea faults has been long in coming and slow to catch on, even among earth scientists, he said.
Chris