What might be the number for how catastrophic the "Next Big Earthquake" in the(near) Bay Area ?

Question

based on the Mercalli Scale

Answer 1

This is totally unknown. The next big one could be in 2 minutes or not for 10,000 or more years. And the degree of damage depends on so many things. There is no way at this time to predict the time or the strength.

For example, we had a 5.8 in LA last month. A few cans fell off the shelf at a K-Mart right over the epicenter in Chino Hills. There was zero damage where I work about 10 miles from there.

A few years ago, a 5.8 in Iran killed 30,000 people.

My point is that the strength number means little in the amount of damage.

Answer 2

Northridge EQ got category low X Mercalli, so anything biger than that must be at least category XI within 15 miles from epiccenter.  1906 EQ caused damage in Santa Cruze area or 100 km away. This information is based on scientific research report after Sichuan quake.  Most steel buildings, new construction and EQ reinforced buildings have high chance to survive base on observation of big EQ at Mexico city.