Fault? It's San Andreas! San Francisco and sub-urban Earthquakes and Geology
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Earthquakes
The San Andreas Fault
Table of Contents
Don't-miss Sights in San Francisco
Content edited for clarity, brevity, continuity and the reduction of redundancy.
                 The original is on Trip Advisor's San Francisco Forum                      


Very entertaining, fun to research and to share — BetterthanBings

Great job! . . . I couldn't stop reading — SunyFLx4

A few facts about San Francisco and Earthquakes
My Loma Prieta     Others' Experiences

Deano.bigfella, Liverpool, on May 27, 2006, asked the Trip Advisor's San Francisco Forum about

The SAN ANDREAS FAULTLine

BetterthanBings; San Francisco:
Well . . . It's a big, long fault and it goes all over the place.
———KPIX has a slide presentation of photographs taken from above the towns of South San Francisco and San Bruno.
———Look for Pinnacles National Monument, Hollister, Berkeley (Hayward Fault), and Tomales Bay on the University of California Santa Barbara's photo tour of the San Andreas fault.
———Monterey County's Parkfield is where geologists think the next big seismic event will take place. There is a battery of scientific equipment installed there.
———Take a walk around the University of California's stadium in Berkeley. It straddles the Hayward Fault. Stanford University's page on The San Andreas Fault and San Francisco Bay.

Wes_Tyler_GM; San Francisco:
The best way to see the fault is from the air.
——–-The Point Reyes Earthquake Walk has fence posts and a path tour all about the 1906 'quake. Crystal Springs Reservoir, in San Mateo County, has spots where you can see fence posts that cross the fault demonstrating how far the ground moved on April 18, 1906.

brodevefla; Jacksonville, Florida:
Seeing the fault's features involves a lot of effort for not so much reward.

bjbert; Northern California:
The view of the scarp from Misión San Juan Bautista is impressive. So are the deformations on the streets and old buildings in Hollister. I worked at a Daly City medical facility when the 1989 quake occurred. It shook the daylilghts out of our new four-storey building. I live in Moss Beach, two blocks from the San Gregorio Fault. I am always interested to know more about keeping emergency supplies, refreshing batteries, water, and rations know more about quakes. I keep emergency supplies, fresh batteries, etc. Here's a cool aerial photo and the United States Geological Survey's Earthquake Hazards Program – Northern California.

Firewind; Boston:
It's a shame that the seismograph on an active part of the San Andreas fault line was removed from right outside the San Juan Bautista sanctuary. But there's a real-time site with automatic reports before – then after – a seismologist has gotten to to them.

bgactor2005; Near Disneyland:
United States Geological Survey has links to several other relevant sites.

brodevefla:
Several outlines of  regional field trips to various and the effects of earthquake activ- ity are here.

girasol; San Francisco:
Taking the Earthquake Trail in the Point Reyes National Seashore.
———Transcript of National Public Radio John McChesney's story: 
Retracing the Path of the 1906 Earthquake broadcast on Morning Edition.
———In Hollister you can see displacement on some of the sidewalks, due to a slow creep. Crystal Springs Reservoir is a visible example of the fault. The valley runs north-south, different than most all coastal valleys, because the fault runs directly beneath it. The lateral movement has created the rift. Fault lines are nor- mally only visible shortly after the movement. Time heals most scars.
———Saint Louis University has a suite of pictures of the after effects all along the rift of The California Earthquake of April 18, 1906. The United States Geological Survey's 1906 historical research on the San Andreas Fault has a picture of the fence posts at Crystal Springs

Firewind:
There's an outdoor exhibit just across the parking lot from the Bear Valley Head- quarters and Visitors Center of the Point Reyes National Seashore. Ask the rangers or docents to point out the two geologic formations that are on either side of the Fault – and watch the peninsula on the west side travel northward at its 1-2" per year pace (save when there's a major quake on the fault).

bayatuning; Stanford:
Public transportation to San Andreas Reservoir Take [San Francisco] Bay Area Rapid Transit (BART) or CalTrain to Millbrae, then (only on business days) SamTrans bus 342 to Skyline Boulevard at Hillcrest Avenue. Go under the Junípero Serra Freeway (280) and you will be at the north end of the Sawyer Camp (a paved bike and walking) Trail, that follows the San Andreas Fault for six miles between San Andreas Lake and Crystal Springs Reservoir. It starts to the left, climbs a short way past a Caltrans maintenance station.
———The trail winds down to San Andreas Dam where you can see a plaque on a rock showing where the fault runs. This earthen dam survived the 1906 Earthquake; the fault runs at the East end of the dam. You'd think the dam would be ripped apart, but this didn't happen.
——–-The trail continues South but is fenced in, so you can't explore the surround- ing territory. I haven't seen any displaced fences along the trail, so I'm guessing the fence and tree line in girasol's link must be somewhere off the trail. The trail is fenced off so you can't explore the surrounding area, it's pretty thick woods anyway with tons of poison oak. there is a golf course, though, on the east side, not accessible from the Sawyer Camp Trail, but perhaps this is where the displaced fence might be.

RS3Sport; San Francisco:
About half way between San Francisco and Los Angeles, on the Carrizo plain you can see the little hills that were formed by the fault, and when I was there, see the cracks that (I assume) are part of the San Andreas Fault. It's interesting out there. It's all desert. You can really see the effects of the fault.

bjbert:
At 16:30 on the First Sunday of some months, there's an Earthquake Hike, spon- sored by Midpeninsula Regional Open Space District, that starts at Los Trancos:
——–-Join the docent . . . at the junction of the Pacific and North American plates and learn about local geology and earthquakes. On this 2- to 3-mile stroll, you'll discover remnants of the effects of the 1906 earthquake, discuss plate tectonics, and learn how to prepare for future earthquakes.
———Meet at the preserve parking lot on Page Mill Road (across from Monte Bello Preserve), 7 miles west of I-280 or 1.5 miles east of Skyline Boulevard. Those driving from I-280 on Page Mill Rd. should allow approximately 35 minutes travel time.


SwingCha; San Francisco:
I live about three miles from The Fault.

tomvegas; San Francisco:
I live on top of the fault.

brodevefla:
Many people do. The question is: “Why?” Choosing to live there seems risky because eventually something IS gonna happen.

SwingCha:
In the USA, heat (the most lethal natural phenomenon), cold, tornadoes, floods, and hurricanes kill people every year. Occasionally, a tsunami does. Total the Earth- quake deaths in the USA since 05:12 of April 18, 1906 and compare it to the number of people killed by other natural phenomena in the USA in the same period.
——–-We all read reports of thousands killed by not-so-great 'Quakes in other coun- tries. Many of them have building codes just as strict as ours; what the they don't have is our stringent enforcement. We pay with money. They pay with their lives.

BetterthanBings:
You don't have to live on a fault line to be affected by it. The Marina District was hit hard by the Intensity 6.1 Loma Prieta 'Quake, October 17, 1989, because it's built on unengineered fill. Liquefaction, meaning the ground becomes gelatin-like, was the big factor there in '89.
                                     
REÜNITE PANGEA!


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A FEW FACTS
Every day in California, the USGS records about a hundred 'quakes.
More than eighty percent of California homes don't have Earthquake insurance.
For every hundred thousand people living in the San Francisco Bay Area in 1906, there was a fault zone.
For every million people living in the San Francisco Bay Area in 2006, there's a fault zone.
The first “Great San Francisco Earthquake” resulted in thirty-five deaths: the Hayward Fault's 1868 7.0 'quake.
San Francisco's Great Earthquake of 1906 had an intensity of 7.9 and killed three thousand people (maybe).
The Loma Prieta Earthquake of 1989 had an intensity of 6.9 resulting in fifty-seven directly-related and six ———indirectly related deaths.* There were
3,757 documented injuries.
The length of 1906's San Andreas Fault rupture was 290 miles; the Loma Prieta rupture was twenty-five miles.
In April of 1906, about 225,000 of San Francisco's 400,000 residents became homeless.
Source: 1906 Earthquake Centennial Alliance
*Public Media (National Library of Medicine and National Institutes of Health)


Dancing in/near San Francisco
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Table of Contents


The following appeared on the 'Net Monday, January 17, 1994 at 16:17.
Minor edits and additions have been made.
The original file describing the events of October 17, 1989,
with others' comments, seems to have vanished.

TEMBLOR
I'm sure we're all sympathetic to the poor people in the SouthLand who have today experienced a 6.6 temblor.
———Earthquakes are neither more nor less frightening than other natural events when they're happening. The big difference between Earthquakes and storms and floods and fires is that you don't know they're coming 'til they arrive. Further, they're a bit different because we're all familiar with fire, moving air and water. When terra firma proves to be terra infirma, it rattles your reptilian core.
———Although it might sound a bit psychotic, the chance of an Earthquake happening is just below the surface of my conscious mind. As a life-long San Franciscan, I'm almost a walking seismograph. I feel 'quakes that people in the same room don't and have won money by turning on a radio to hear the reports. Further, when they happen here, I usually call their intensity very closely.
———The only 'quake that really scared me was the 5.7 of March 22, 1957. During the few seconds that it shook, I learned the meaning of “terror”. I also instantly had a profound understanding of the insignificance of Man in the eyes of Nature. She just plain don't care nuttin' 'bout us. To Her, we're of less signifi- cance than the ants we kill when we walk our streets.
———When Loma Prieta hit, I was in the shower and had just soaped m'body. I instantly knew, and said aloud “This one's different. People died.” I jumped out of the shower having to use a towel to turn the round 'knob (since replaced with an oval one). I stood atop the stairs, a hand on each wall, as the house danced to the atonal music of objects falling and breaking. The electricity went off.
———When the shaking stopped, nude but no longer dripping because the soap was beginning to cake, I went to the basement to check the water and gas con- nections. I then finished showering.
———The bedroom has a Southern exposure so I was able to use the closet door mirror to comb my hair. At about 17:30, it was dark and I went to examine the damage. The house was a mess, but not nearly as bad as many others'.
———Dinner was to've been prepared in the oven. Because the electronic igni- tion and would not work, the meal was cooked atop the stove.
———For a reason I do not know, I stepped outside after dinner. A neighbor had rigged a television set to a car battery. Many of us neighbors sat around drinking beer and watching the television during the very warm evening.

The reports of damage from here would make one not here think that we were all but wiped off the face of the planet. I'm very wary of believing the reports now coming from Los Angeles. What I do know, however, is that the freeways that are down will cause another disaster because of Angelinos' almost total depend- ence upon the single-occupancy automobile.

Earthquake damage is dependent upon many things. One, of course, is the temblor's intensity coupled with one's proximity to its center. The Loma Prieta 'Quake was centered approximately sixty linear miles (~100km) from City Hall.
———Another very important factor is the land upon which structures stand. The Marina, where much of the worst damage happened here, is fill. Wash- erwoman's Lagoon was filled in to create a site to hold the 1915 Panama-Pacific International Exposition. After The Fair, most of the temporary structures were replaced by very nice housing.
———Sandy soils have a tendency to “liquefy” during 'quakes. That's what hap- pened in the Marina District. In the valley around Northridge, the soil is mostly naturally-deposited sediment. It's similar to fill but probably more stable. Con- struction is, of course, another extremely important factor. One of the reasons for the great post-'quake tragedies in Managua, Guatemala City, and Mexico City in recent decades is the poor construction materials and techniques used.
———We'll probably learn that the same is true for the damaged structures in the Southland just as we did after the hurricane that hit the East last year.

I predict that looting in Los Angeles will be minor and that the number of crimes reported there in the next few days will be a small percentage of normal.

Although the Alaska 'Quake was the strongest that any of us can remember, the greatest 'quake that's known to've hit this country was on Missouri's New Madrid Fault. When next it moves, it will probably result in the greatest natural disaster in this nation's history, dwarfing ours of April 18, 1906.
———I say that because that part of the world has neither the building codes nor consciousness of Earthquakes that we do yet they're at constant risk, just as we. What they don't have is the regular reminders that we have.

I feel for the people in the Southland just as they did for us. But I can almost guarantee that the damage isn't nearly as severe as news reports would have us believe.

The Loma Prieta 'Quake cost me, in spite of having Earthquake insurance, $33,000. I received nothing from the Federal Emergency Management Agency (FEMA).
———We're all familiar with how insurance deductibles work: You have a loss. You pay the fixed-amount deductible. The insurer pays the balance.
———Earthquake insurance has a 10% deductible. Based on the above, you would think that, if you had a $100,000 loss on a property insured for $200,000, you'd pay $10,000 and the insurer $90,000. But that's not the way Earthquake insurance works.
———The deductible in Earthquake policies is 10% of the insured amount, not the amount of the loss. Therefore, if your property is insured for $200,000, your deductible is $20,000 regardless of the amount of the loss! [That's no longer true: the deductible is now 15%.]

There's more:
———Your property is damaged by a temblor. It then catches fire and is com- pletely destroyed. How much is the insured loss?
———No easy answer. The fire coverage will pay the amount that the insured property was worth at the time the fire started. Now, since the fire started after the 'quake damage, what was the property worth after being damaged by the 'quake but before the fire started? When that's answered, you learn what the insurer will pay.
———Unfortunately, the logic of this is quite simple and easy to understand. The principle is applied in many areas of the law.

________________________________________
JIM GRIMES: Wednesday, January 19, 1994 10:01
(Jet Propulsion Lab, Pasadena)                              

Finally, I feel for the people in the Southland just as they
did for us. But I can almost guarantee that the damage isn't
nearly as severe as news reports would have us believe.


James Grimes> Your report from Loma Prieta was very descriptive.

A kind comment for which I thank you.

JG> Quick question.
JG> what is the perception that news reports have given?

Maybe I'm being victimized by the words and images but I'm beginning to believe that what I said above is wrong and that the damage is far more extensive than the initial reports would've had us believe.
———The Hong Kong query is a more distant view of the perceived situation.

Most San Franciscans have been to your part of the world. We look at the maps, find our landmarks (Hollywood, DisneyLand, Exposition Park, Watts Towers, POP, NuPike [yes, I know they're gone], etc.) and have some idea of how exten- sive is, and isn't, the damage. But people from the Far East, say the Moscows, Parises, Londons, Ha[a]rlems, and Cairos can't do dat just as people in the Far West, say Honolulu, Alice, and Hong Kong, can't do dat.

JG> At least one person I've heard from was convinced
JG> that the entire LA Basin is now in the Pacific ocean.

Not unlike what they thought about us and our situation.

JG> Happily that's nowhere near reality.

As a San Franciscan, I am compelled to withhold comment.

JG> Heh – well that's not fair. If the entire Pacific Plate portion of California
JG> slipped off into the Pacific (if I remember the location of the San Andreas
JG> correctly), all of LA would be gone, but only part of SF. Humpf. ;-)

Nope. All of San Francisco is on the North American Plate. I think all of Los Angeles is on the Pacific Plate.

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OTHERS' EXPERIENCES
Firewind:
I am reminded of where I was during the 1957 SF quake. (I've since remembered it to be in 1958, but that's a conflation with its 5.8 magnitude.) Anyway, I'd just been to the hospital on St. Joseph at Geary. We were getting gas at a station across Geary Boulevard. It was in the days when the attendant checked oil, water etc. Well, that guy came out from under the hood of our big ol' road hog shaking the dipstick like he was gonna use it on us. He thought I was bouncing in the back seat. All mom could do was point over at the big glass display windows on the front of the department store across the street as they popped out.
———Second: I slept right through the Sylmar quake in LA. I'd just been dis- patching for some twelve hours during one of the UC, Santa Barbara riots – at which time we had an army of police and fire personnel from all over the state camped beside the public safety building – and gone to bed at 04:00. When I woke up later that day, and saw everyone that had been doing riot duty huddled around TVs, and they said, “You didn't FEEL it?! It didn't throw you out of bed?!” . . . I again experienced cognitive dissonance, or overload, or something.

OK, one last one. This stuff fascinates me, and I try to get to many volcanoes. When my son was about five, I took him to the rim of the deeper, active part of Kiluea. There were bunches of fresh and not so fresh flowers and fruit right at the edge. He asked what they were for. I said I supposed they were offerings to Pele. Well, that was enough for him. He was pickin' 'em up and puttin' 'em down back to the car like I've never seen before or since . . .

***
Imagine being in Boston at a banquet during a meeting of the fire chiefs of the largest cities around the world, when the Loma Prieta reports came in. First we saw the San Francisco chief called aside. Then the host gets on the microphone and says, “I have a very serious announcement. There has been a major earth quake in the San Francisco Bay Area, and the Bay Bridge has collapsed.” I grew up, and spent the first half of my adult years in the San Francisco Bay Area. I helped to formulate the plans for just such an event . . . the pit of my stomach felt like a liability.
———Then imagine going upstairs to a TV, and seeing Don (Steve?) Sanchez on a nationwide constant live feed (until Peter Jennings arrived to take the helm from NY) as if I were watching back home in San Francisco. Cognitive dis- sonance. Oh, and watching the TV, I was standing next to the San Francisco fire chief, who was (would have been) technically in charge of the City of San Francisco at that moment? He was nine kinds of emotion tightly wrapped, to paraphrase the description of Hotlips Houlihan in the movie M*A*S*H*.
———Anyway, we got the fire chief on a charter to DC, where he joined the northern CA congressional delegation on a military plane. As the fire chief told me later, arranging for his aides to meet him was difficult. When they took off, they had no idea where they were going to land . . .

Be safe.

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