Thursday, June 9

OUR ISLANDS ARE RISING because of earthquakes



This just extracted from Kerry Sieh's latest mail:

"My crew is still in the Nias/Banyak region, filling in gaps in our data, but we now have a pretty good map of uplift and submergence associated with both the Dec and March earthquakes. The whole region tilted during the two earthquakes: Simeulue is up on all coasts, higher on the west than on the east (1.65 meters max is at Lasikin airport). Nias is up on the west and generally down on the east (highest uplift is about 2.9 meters near Lahewa. Submergence is less than a meter at sites on the east coast). The Banyaks are up a meter or less west of Pulau Tuangku and down from Pulau Tuangku east)."

I asked for Kerry's opinion on the likelyhood of a major quake/tsunami in the Mentawai area:

"There are so many unknown's in the details of what happened in previous earthquakes that it is best to keep things simple. We know that essentially all of the Sumatran section of the megathrust north of the equator failed in the two giant earthquakes of 2004 and 2005. And we know that none of the section from Siberut to Enganno (0.7 to 5.5 degrees south) has failed since 1833. Furthermore, we know that the most recent ruptures of that section occurred in 1797 and 1833 and that each of these generated big tsunamis along the local coasts. Finally, we know that giant earthquakes occur along this section about every two centuries. Thus, another big earthquake is likely within the next few decades.

To make a more precise, valid prediction at this point is not really possible, in my view."

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