When The Earth Moves: Mega-Earthquakes To Come?

**GlennO** · June-17th-2010, 02:46 PM

For those of us that follow the shaky subject of earthquakes. The link gets you to a PDF on the menu same as the thread title (2nd one down dated June 15). Very good analysis from the insurance industry perspective!

Thought Leadership - Aon Benfield

**SonSeeker** · June-17th-2010, 03:33 PM

Hey Brother!
Since none of this report mentions your neck of the woods, I guess this must be good news.

But it does seem strange that only a small portion of the west coast was discussed, any idea why?

**GlennO** · June-17th-2010, 07:15 PM

Hey John!

More importantly, any subjective indications that the AZ trespassing tide is ebbing?

In answer to your question, the much studied and feared San Andreas is a strike/slip type fault mechanism. These mechanisms generate damaging quakes but the recurrence interval is typically more frequent, releasing the stored energy as the plates grind past each other. Not that a magnitude 7-7.5 is anything to sneeze at!

The subduction type fault mechanism releases exponentially greater quakes in the magnitude 8-9 range, hence the "megaquake" focus of the study. Megaquakes occur less frequently, but the slow-motion collision process of forcing one plate underneath the rising plate results in a tremendous release of energy, the duration of shaking over a longer event period, over a greater area in contrast to the strike/slip quake.

The insurance industry sponsored report focused upon exposure of their capital to the unanticipated high cost of megaquakes. In this case, self-interest/greed probably produced the most realistic assessment/ identification of risk.