An Undeniable Hard Stop

Unlike Climate Change, the Cascadia Seismic Threat Has An Undeniable Hard Stop

When is the next Cascadia Seismic Catastrophe? The world-class petro geophysics geniuses are so bashful. Would they sacrifice last minute $Bs to warn neighbors? Communities? Cities? States? The Conscience of Exxon already tells us, why would they bother? This possibly explains why no one seems to have asked Exxon about any of this. Exxon under oath? Cancer cured first. Next would be cold fusion.

So we need our own analysis. In 2012 the USGS reported the intervals between the 42 known catastrophes. We only know of 41 intervals. We know the last M9 disaster here was 1700. Geologists admit their science cannot make predictions even given their increasing understanding of Earth’s crust structure and past behavior. What can we conclude from considering these pathetically few numbers?

Mathematicians explain statistical properties with clever tools like the Galton Board. Patterns emerge from testing and retesting random occurrences. The Galton Board experiment produces repeatable patterns that are generalized as “the normal distribution.” 

For 10 years the 2012 USGS Paleoseismicity report has been taken as the credible characterization of the statistical probability of the next west coast Cascadia event. Interpretations of the 13 authors added up to at least 16 citations of different probability distributions, starting with the 41 known intervals. For some unexplained reason Oregon seismic policy leaders have settled on a likelihood of 37% in the next 50 years for the next catastrophe. Controversially, fifteen other USGS probabilities were discarded from consideration. Authors of this USGS analysis declined to compute the sum total probability from all known causes, so 37% itself is a low estimate. We also do not know why all 13 contributing geologists chose a 50-year period for their computation.

Naturally some readers would want to verify these numbers independently, given that a collapse of the Oregon economy is on the table, sooner or later. The policy guidance in force today simply claims it will be “later.” A second analysis, termed “Armchair Quarterback” (ACQB) is offered for comparison. The 2002 Petersen paper discussed 50-year probabilities with out disclosing “why 50 years”.

With so few data samples, postulating a probability distribution was deliberately avoided with ACQB, because assumptions do not help when the dataset (41 numbers) is so small. Nor was a 50-year window considered. The ACQB analysis checks to see how many historically observed quiet time intervals have already been surpassed since 1700. The result is that 93% of quiet time intervals were surpassed in 1993. If you believe in “regression to the mean” (taken from assuming a normal distribution of quiet times), we are well past the mean and are quickly running out of remaining intervals observed in the last 6,000 years. This analysis
says it’s going to be “sooner”
has not had any attempts to refute it by anyone commenting so far.

The ACQB analysis suggests that the CEI Hub is facing a hard stop in the near term. Petro industry geologists so far are totally disengaged from the impending economic disaster poised to take down their own highly vulnerable infrastructure along with the west coast economies.