‘Random’ Events and California Earthquakes

Methinks your esteemed editorialist (July 23) gets onto some very squishy ground trying to reassure us that earthquakes are purely “random” events.

My dictionary defines “random” as an occurrence “without definite aim, purpose or reason.” An example would be the recent case of a demented man running amok on the Staten Island Ferry and stabbing several people with a sword--an utterly unpredictable event.

But as we all know, there’s a very definite reason for earthquakes: the buildup of pressures as the earth’s tectonic plates migrate. If we could measure these pressures precisely, we could predict exactly where and when the next earthquake was going to occur. Indeed, the science of seismology is heavily dedicated to making such measurements.

In this context, the asserted randomness of earthquakes is just a way of saying that to date our measurements don’t have the requisite precision. But the occurrence of several earthquakes in the same locality within a short time is indisputable evidence of a buildup in pressures, and a basis for inferring either (a) that pressures have been dissipated, or (b) that there is more pressure in that locality to be released. Prudent people obviously would focus on possibility (b).

In terms of the editorialist’s baseball analogy, a manager who dismissed a .300 hitter’s slump as only a statistical aberration wouldn’t hold his job long. He’d better be looking for reasons.

GLADWIN HILL

Los Angeles