6: Tsunami could be 1,000-year event

6: Tsunami could be 1,000-year event

There are 21 comments on the BBC story from Mar 16, 2011, titled 6: Tsunami could be 1,000-year event. In it, BBC reports that:

Tsunamis on the scale that hit north-east Japan last week may strike the region about once every 1,000 years, a leading seismologist has said.

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“Geologist [I'm Climate Change]”

Since: Mar 07

formerly Nuneaton

#26 Apr 12, 2011
Part 7: The timing with range r/lx.

Active r/lx of one range is done with timing expectations of ~35m per megathrust with 3 in all at the range. The 1st 2 scenarios do not take into account any expectation of continental decompression during r/lx as this is likely incorporated into the runout. The 1st 2 scenarios also do not incorporate any condideration of plate lurch of the Mongolian plate during the event which is a fraction of the ~S. directed vector assumed by later r/lx of the Ryukyu backarc basin.

For those modelling chaos and annihilation during r/lx note that the runout may be an overestimate, and may be less than my ballpark figure per megathrust (relatively good news for the locals at the time of the next event). For those modelling recompression interval time also note that the recompression interval time may be a considerable underestimate (Ranges are mountains, the runout is therefore expected to be less then the recompression interval time!).

For the 1st scenario, one range of the pair undergoes r/lx with a SE. vector decribed in part 6: with 35m per megathrust. The total runout spread between all the megathrusts along the SE. vector is approximately 330m total, and the recompression interval time is ~3928+-1000 years (see provisos for the huge error bar). The expected r/lx datew would have been 1917+-1000BC.

For the 2nd scenario with 2 ranges undergoing r/lx, there is a foothills megathrust and 2 nappe pairs undergoing r/lx with ~35m per megathrust with the range getting out of the way and plate lurch (unaccounted for) due south.
With 5 megathrusts involved in the r/lx the runout is close to 400m total when spread between the megathrusts in the way of the surge, and the recompression interval time is then 4762+-1000 years.
The expected date of the r/lx would be 2751+-1000BC.

For the 3rd scenario, range r/lx occurs with decompression of the Mongolian continent to the backrift at lake Baikal which undergoes a sudden rifting episode, and deepens. The scenario also does not include associated S. directed plate lurch of the Mongolian continent (which may diverge to SSE. vector, and add to the recompression interval time.

In this case the 5 megathrusts are involved with both ranges undergoing r/lx and approximately 120m of decompression of the Mongolian continent occurs over a matter of days to weeks following the r/lx with the Koreas-Manchuria backarc basin being moved bodily SE. by the event.

Total runout spread between all the megathrusts in line with and including the Hondo zygomorph is approximately 520m total, with a recompression interval time of 6190+-1500 years.(note the bigger error bar).
The event would have taken place about 4179+-1500BC.

{Insert more original godzilla movie monster noise about here}.

THis should be a decent target for looking at ages of Palaeotsunami in the flat land around Vladivostok.

Have a nice day: Ag

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