Liquifaction,Plays a very big role in resulting damage from earthquakes!

Yup. Along with a whole lot of other things.

If the house is still standing after a quake, my biggest concern will be gas leaks and fire. I have 4 kitchen size fire extinquishers around the house. Thats not going to be enough. But if the water mains are broken, even a tanker truck wouldn't be enough. Hopefully the car will be undamaged so we can evac if necessary. So many unknowns, its mindboggling.

If I were living in southern California today (I grew up there in the 1960s/70s - the Sylmar quake experience stands out), I think these would be my preparedness priorities:

1) Shelter-in: the ability to live outside (tent, screenroom, camping gear, portable toilet, water storage, portable shower). Portable radio + batteries.

2) Backpack in car: in case you're not at home when the quake hits and roads are impassable. Also in the car 24/7: hiking shoes/socks, seasonally appropriate jacket, hat, umbrella, highly detailed area map, first aid kit, PSK (including Micropur tablets), water bottles, flashlight/headlamp/batteries, cash (hidden), leather gloves, prybar. Portable radio + batteries (extremely important).

3) Know thy neighbors: and see if anyone would help increase preparedness awareness on your own block. It's in everyone's interest to reduce the risks of fire (ex: know whose homes have gas and having the tools to shut it off), guard against looters and otherwise join together in the aftermath to help fill in the void left by emergency services perhaps being preoccupied elsewhere. Families should have added incentive to participate because children may be home alone when a quake hits.

4) Workplace preparedness: Is this a priority for your employer? Stash what you can at work, too.


I'd assume the worst about the government's preparedness.

Dagny, you are absolutely right. I might add that I keep a hatchet and collapsed Sven saw in the car, as well.

These personal preparations may be moot, as I see by the papers today are asserting that the PROCESS THAT SHALL BE NAMELESS is raising its ugly head. Without funding, any good plan is severely restricted......

A bit cryptic for me. What process is "the process that shall be nameless?"

What the government does or doesn't do or may or may not fund, is irrelevant to my personal preparedness.

In a major disaster here, I assume government will do nothing for me -- no services, no protection.

Living in DC, even at the best of times I have learned to have low expectations for government services.

There is currently a dustup in Congress relative to funding FEMA - the agency may shut down fairly soon.

I agree that one should be prepared on a personal level. That is the help that is immediately available. My family and neighbors are much more handy than any government services.

However, my experience in the provision of services, particularly in emergencies, has been more positive than yours, evidently. They do come along and it works nicely with local efforts.

If we use the 1906 San Francisco earthquake as a guide to the general level of destruction for a major quake in a large CA city then we get the following ...

* About 0.7-1% casualties amongst urban population
* About 56-75% of all city residents homeless after the quake
* Most destruction caused by fires after the earthquake

Here is the Wikipedia summary of the fires after the 1906 event:

"As damaging as the earthquake and its aftershocks were, the fires that burned out of control afterward were even more destructive. It has been estimated that up to 90% of the total destruction was the result of the subsequent fires. Over 30 fires, caused by ruptured gas mains, destroyed approximately 25,000 buildings on 490 city blocks. Worst of all, many were started when firefighters, untrained in the use of dynamite, attempted to demolish buildings to create firebreaks, which resulted in the destruction of more than 50% of the buildings that would have otherwise survived.
... As water mains were also broken, the city fire department had few resources with which to fight the fires. Several fires in the downtown area merged to become one giant inferno. Brigadier General Frederick Funston, commander of the Presidio of San Francisco and a resident of San Francisco, tried to bring the fire under control by detonating blocks of buildings around the fire to create firebreaks with all sorts of means, ranging from black powder and dynamite to even artillery barrages. Often the explosions set the ruins on fire or helped spread it."

This potential problem with fires is probably even worse for Los Angeles today because the density of structures has increased considerably. The worst-case outcome could potentially be real firestorms erupting in some high-density neighborhoods - since without water it would be impossible to put out the fires quickly. I doubt that firefighters will use dynamite these days - but we have portentialy many more sources of fire due to various industrial processes.

And going back to the casualty and homeless rates, if we apply them to the L.A. city region:

Casualties = approx 21,000 - 31,000 people
Homeless = 1.7 - 2.3 million people

and this is only using the population figures for Los Angeles (not counting Orange County or other bedroom communities).

Which raises an important point ... how many of these homeless people have EDC kits prepared and ready to go? And if their homes are destroyed by earthquake or fire - doesn't this mean that any emergency supplies stored inside their houses would also be destroyed as well?

Pete2

Don't forget that buildings in California today are built to far higher standards (though not necessarily perfect) than the structures present in 1906 San Francisco, which included many unreinforced masonry buildings.

For what area of destruction are you deriving your casualty figures? You will get maximum destruction at or near the epicenter, but damage will tail off in surrounding areas, subject of course to local factors, such as geology and soils.

I would be very surprised if authorities have not already gamed this scenario, perhaps at an even higher level of sophistication that we are capable of, incredible as that might seem.

Of course, I am no stranger to surprises......

I am a geologist by training, and have lived most of my life in earthquake prone regions (grew up in the PNW, and the last 25 years in Alaska), so I'm kind of interested in this stuff.

I don't wish to minimize the danger of a major earthquake occuring under a major west coast city such as Vancouver BC, Seattle, San Francisco, or LA. However, it is also good to keep in mind that damage and destruction in an earthquake (and resulting tsunami) is generally highly variable over an area. Extrapolating damage from the worst hit area across an entire region can be misleading. At the same time it is prudent not to underestimate the risks.

Damage from an earthquake can occur in a number of ways. The direct ground motion can cause buildings, bridges, and other structures to collapse. The intensity of ground motion depends on how near the epicenter is (map view) and how deep it is. The damage is also highly dependent on local soil and bedrock conditions, and how long the quake lasts. Landslides triggered by the quake can be extremely destuctive, but tend to be localized, depending on topgraphical relief and soil conditions. Structures built directly across a fault which moves will be heavily damaged, but this tends to be a very narrow linear zone. Tsunamis can come from distant earthquakes, or be locally generated. In either case tsunami damage is very dependent on local coastal bathymetry. Some areas are very low risk, and some are high risk.

The 1964 Alaska Earthquake provides a good illustration of this. At 9.2 it is still considered to be the 2nd most powerfull earthquake recorded in modern times. Some of the most graphic images of that earthquake were from Anchorage. But it is well to remember that even in Anchorage, the degree of damage varied dramatically over short distances. The Turnagain area and downtown were severly damaged by landslides, but much of the rest of the city was not. The only deaths directly resulting from the earthquake were the 9 people killed in Anchorage. The other ~124 deaths were elsewhere (16 outside of Alaska), resulting from tsunamis.

Based on actual damage in '64, and more recent geological research, a seismic risk map has been compiled for present day Anchorage: http://www.muni.org/Departments/OCPD/Planning/Planning%20Maps/Anch_Bowl_Seismic_8x11.pdf

The USGS, NOAA, and other agencies attempt to compile similar maps for other threatened cities. For example, in the Seattle area there is a map showing the relationship of earthquake risk to important infrastructure "lifelines" at http://geomaps.wr.usgs.gov/pacnw/lifeline/index.html
For Seattle tsunami hazards see: http://www.pmel.noaa.gov/pubs/PDF/wals2794/wals2794.pdf

Again, I'm not trying to minimize the risks, only to keep them in some kind of realistic perspective.