What city is more prone to a catastrophic earthquake? San Francisco or Los Angeles?

[Clarks]

Not to scare anyone one, but what the heck, might as well. During the Mission days an earthquake released a landslide off one of the Channel Islands, it kicked up a Tsunami that dumped a fishing boat near the steps of the Santa Barbara Mission.

That fault is supposed to release again, anytime, (geologic time) that would kick up a Tsunami that would take out, Ventura, Oxnard, Malibu, Santa Monica and all the beach towns to San Diego.

It is predicted that there will be almost no time to evacuate and casualties should run around 300,000 killed, sleep well.

[Voyageur]

Originally Posted by Clarks

Not to scare anyone one, but what the heck, might as well. During the Mission days an earthquake released a landslide off one of the Channel Islands, it kicked up a Tsunami that dumped a fishing boat near the steps of the Santa Barbara Mission.

The Santa Barbara Mission is over two miles inland and over 300' above sea level. So this claim is rather impressive. What earthquake was this? The 1812 earthquake was the most destructive to Santa Barbara during the Mission era, and while it is associated with some mention of sea waves, I cannot find any suggestion of such a colossal event as to toss a boat inland that far and that high.

This is a report of an otter hunting ship being thrown half a mile up Refugio Canyon, though the elevation of the canyon at this point is approximately 45'. Is this perhaps what you're referring to? Anyway, even this report is highly dubious, for a variety of reasons.

That fault is supposed to release again, anytime, (geologic time) that would kick up a Tsunami that would take out, Ventura, Oxnard, Malibu, Santa Monica and all the beach towns to San Diego.

It is predicted that there will be almost no time to evacuate and casualties should run around 300,000 killed, sleep well.

Huh. Well, you're right. Someone has predicted that. You, for example. But not the U.S. Geological Survey and Moss Landing Marine Laboratory.
http://137.227.239.66/reports/reprints/Fisher_MG_224.pdf

Per the report cited above, a quake similar to the 1812 earthquake can be expected to produce landslide that results in a small tsunami, as in 1812, which would mean a runup to about 2m (6.5 feet). Also, the area of shoreline affected would be very narrow - about 10 km (6 miles).

Of course, there is always the possiblity of a massive submarine landslide that can produce a much larger tsunami. And they can occur, as you say, anytime (on a geologic time scale). But since geologic time is measured in millions of years, and since the entire California coast is subject to these landslides (not just the Channel Islands region), issues of when and where are largely irrelevant to this discussion.

[Voyageur]

Originally Posted by gogetta

I know both are hotbeds for earthquake activity and either one could be hit with a devastating earthquake at any time. I am not asking which one will get hit first, but which one is more prone to it happening and which one is more prepared for when it happens.

So which are is more proned to earthquakes? LA of SF Bay Area?

Well, I would think part of this question lies in which is more likely to get hit by a devastating earthquake first (let's define a "devastating" earthquakes as 7.5M+). And the consensus is that the southern San Andreas fault is more "due" for a large quake than the northern portion. That doesn't mean one can hit SF before LA, but the latter seems a much more likely target for the next "Big One".

[DMenscha]

Both cities are the most prone to a catastrophic EQ.

[Chelito23]

I agree that they both have their advantages and disavantages, so neither is better or worse or more dangerous. Fortunately both cities are relatively well prepared.

I think communities like San Bernardino, Palm Springs, Palmdale are at the greates risk because of their extreme proximity to a stretch of the San Andreas that is supposedly overdue for a major quake.

[Charles]

Originally Posted by Chelito23

I think communities like San Bernardino, Palm Springs, Palmdale are at the greates risk because of their extreme proximity to a stretch of the San Andreas that is supposedly overdue for a major quake.

Risk is the product of probability and impact. Even if it was 10 times more likely that an earthquake would hit Palmdale, it would be less risky than one hitting LA because the impact would be so small in comparison to one hitting LA.

[TimC2462]

Originally Posted by gogetta

I know both are hotbeds for earthquake activity and either one could be hit with a devastating earthquake at any time. I am not asking which one will get hit first, but which one is more prone to it happening and which one is more prepared for when it happens.

So which are is more proned to earthquakes? LA of SF Bay Area?

I would think it would go either way. When the '89 earthquake occurred in the bay area, it was so catastrophic that a section of a bridge collapsed. A huge factor is the building design that can withstand earthquakes. Look at Haiti -- third world country with much older building and nearly non-existant building codes to withstand earthquakes.

Most newer buildings in my county require that new construction meets the requirement of earthquake resistant code, something to that effect.

[Gentoo]

I noticed someone mentioned the Newport-Englewood Fault as a source. Believe it or not that would also put San Diego at risk.

Not that it has anything to do with the question. I'm just saying that all the big cities in Ca. are vulnerable.