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Loma Prieta (1989)

An unusual Tuesday, 5:04pm.

California has been extremely fortunate in terms of the timing of its urban earthquakes. The San Francisco earthquake of 1865, the Hayward quake of 1868, the 1906 San Francisco temblor, the 1971 San Fernando quake, and the 1994 Northridge event all struck in the early morning hours, when most Northern and Southern Californians were either home in bed or preparing to go to work or school. Even the tsunami generated by the 1964 Alaska earthquake that devastated downtown Crescent City in the northwest corner of the state arrived in the predawn hours. During these events people were scattered about, for the most part in single-family residences.

On a normal Tuesday in the San Francisco Bay area, 5:04 PM would have been the worst of all possible times for an earthquake to strike. It was a time when people would have been in large, vulnerable clumps. Crowds of workers would have been emptying into downtown streets just as glass, bricks and marble parapets came hurtling to the sidewalks. For those already headed home, the double decked bridges and freeways would have been clogged with traffic.

But Tuesday, October 17, 1989, was not a normal workday. The third game of the World Series was about to be played at Candlestick Park between the two local major league baseball teams. Many workers, preceded by schoolchildren, had already arrived home and turned on television sets. Traffic on the various bridges and freeways was much lighter than usual.

A few seconds after 5:04 PM the earth slipped under the Santa Cruz Mountains and the seismic waves radiated outward toward densely populated areas far from the epicenter.

Besides the vicissitudes of human activity, there were a number of natural factors that mitigated the destruction. The state was in the midst of a drought and the many reservoirs in the Bay Area were extremely low. Had they been at normal or above normal levels there could have been a repeat of the Saint Francis Dam disaster. The magnitude of the Loma Prieta earthquake was in the moderate range. 60 times as much energy had been released from the shallow point of rupture just offshore of San Francisco in 1906. This time the focus was deep and was located under a dense forest 60 miles to the south of San Francisco. The period of shaking, 8-15 seconds, was half the expected time for the size of the quake and far less than the one minute in 1906.

Nevertheless, 63 people died, 43 on the same segment of Oakland Freeway. 3800 were injured, 28,000 structures were damaged, and more than 12,000 people were left homeless. At a price of $6 billion for repairs, the Loma Prieta earthquake was billed as the costliest natural disaster in the nation's history at the time.

Lloyd Cluff, the chairman of the California Seismic Safety Commission, surveyed the debris-strewn streets of San Francisco, the broken Bay Bridge and freeways, and the ruined downtown of Santa Cruz from a helicopter and said: "I've looked at some 25 earthquakes in my career all over the world and we were very lucky."

Tuesday was unusual in another way.

Sixty million television viewers in this country and millions elsewhere were transfixed by the world's first prime time earthquake. It was the first earthquake to be almost broadcast live — almost, because the power went off at the moment of impact and it took the electronic media varying amounts of time before getting back on the air. When the various channels and stations were finally up and running, viewers who had tuned in for a game had ringside seats at what was portrayed as a widespread catastrophe.

For the first time the reality of the event — for those who were not present — became the perception of reality gained from a small screen. The difference with written reports was that the electronic portrayal had greater immediate impact and was instantaneous. This left room for greater distortions.

The earthquake unfolded in the following manner:

The October weather was balmy. There was none of the usual fog and wind; rather, it was still, hot, and a bit sticky. Earthquake weather, some thought later.

The camera in the blimp panned over they clearly etched skyline of downtown San Francisco. Sports announcer Al Michaels intoned: "One of the most spectacular vistas on this continent, any continent! Downtown San Francisco is the background and we zoom in to Candlestick Park. For the first time in 27 years a World Series game will be played in Candlestick Park. The Battle of the Bay continues."

The players were warming up and the ABC television announcer was describing the highlights of the previous game. There was a picture of José Canseco rounding the bases and then the image of a baseball player in his prime dissolved into visual static that resembled random patterns of tweed or the flickering hallucinations of migraine sufferers.

The first thing the spectators noticed was a low roaring noise. Then the shaking began. The glass in the luxury boxes bowed, and the light towers swayed, dust rose in the air. There were scattered yells of "earthquake," then silence. When the short period of shaking ended, there were cheers and a spontaneous celebration of survival.

Ballplayers called to their families in the stands to come down onto the playing field where they clutched each other. These gods who strut and chew and spit became mere mortals. They were scared and uncertain, like the people in the stands. The players looked childlike in their uniforms that were no longer suitable for the occasion. The erudite baseball commissioner postponed the contest, stating: "Ours is a modest little game."

As the spectators and players made their way home on the jammed freeways they saw a column of smoke rising over the Marina District.

On very shaky ground—

The Marina District is a rabbit warren of million dollar plus homes and condominiums in the high-hundred thousand dollar range jammed together in an 8 x 15 block area fronting on San Francisco Bay. Living in the one half square mile area are 14,000 residents.

Directly on the Bay are a yacht club, a marina, and a large commons used primarily for exercising and kite flying. The residential area is bounded on three other sides by the remnants of the city's military past and its commercial presence: the Presidio to the west, Fort Mason to the east, and Lombard Street on the south.

In a city dominated by hills, the Marina District is distinguished by its flatness. So were other areas that were particularly vulnerable to shaking in 1989 such as the Oakland waterfront and downtown Santa Cruz and Watsonville — all distant from the point of slippage. What these areas and others around San Francisco Bay have in common is the loose soils on which they were constructed — either the alluvial deposits of rivers or the man-made lands that were recognized as being hazardous as far back as 1865.

The Marina is a good example of what happens when structures are built on ground that has the potential of turning to think soup. The significance of what occurred in the Marina District was outlined by two seismologists. Thomas C. Hanks and Helmut Krawinkler wrote in the introduction to the 1991 special issue on the Loma Prieta quake published by the Bulletin of the Seismological Society of America:

"The Marina District holds a special place in the Loma Prieta earthquake consciousness. It is the latest chapter in San Francisco's long and sad history of recognizing the special problems of the seismic response of young Bay muds and artificial fill only after earthquakes occur, in 1865, 1868, 1906, and again in 1989. It is a reminder, too, that neither are the educated and affluent immune from the effects of earthquakes, although it remains to be seen what this politically active and powerful group of residents will extract from their local, state and federal governments in the way of earthquake hazard abatement. Finally, the damage and destruction in the Marina District is a case study for the profession in the great diversity and complexity of the relationships between earthquake ground motion and resulting damage."

To understand the Marina District is to be knowledgeable about its underpinnings. In California, we are what lies beneath us; and we are never sure what that consists of.

Seven miles east of the offshore San Andreas Fault, bedrock is an ancient, stream formed basin buried 200-300 feet under the heart of the Marina. The rocks are Franciscan and serpentine, the latter being the official state rock. In northern and central California the Franciscan and serpentine formations dominate the North American plate while the Pacific plate is made up of granite and metamorphic rocks.

These basement rocks have different sources, different ages, and come from different places. The words geologists use to describe them are assemblages, exotic terranes, and melanges. However, it was an historian who has best portrayed the bedrock dichotomy of this portion of the San Andreas fault.

By happenstance, Arthur Quinn used my home ground as the setting for his description. In his book "Broken Shore" he compared and contrasted two Peninsulas — the Point Reyes peninsula on the Pacific and the Marina Peninsula on the North American plate. He peered into the earth and wrote:

"Point Reyes and Marin are not merely contrary in their orientation, one to the land, the other to the sea; they differ in their very substance. The foundation of Point Reyes was laid in granite — gray granite, speckled black on white, crystalline, solid as rock should be, refined deep inside the Earth, risen somehow in its purity to the surface, a thing from which monuments more lasting than human memory can be wrought. The larger Marin Peninsula has its foundation in less exalted stuff, matter in fact so common, so heterogeneous, its manner of coming to be is a deep puzzlement. Franciscan Formation is the name attached to this perplexing mixture of rocks on which the Marin Peninsula is founded. A 'nightmare of rocks,' one guidebook called it, a nightmare for anyone who wishes to comprehend it. And within this nightmare there is one rock characteristic of the enigma. A greenish rock, sometimes a mottled blackish green like the Bay on a clouded day, it is a kind of soapstone, a little slimy to the touch. This greenish, slightly slimy rock is aptly named serpentine, the serpent rock. Moreover, it bears with it, like its rattles, the most arresting minerals of the whole Franciscan formation, minerals for which there is no equivalent in the austere purity of Point Reyes: the lucent, aqueous crystals of the bluecrist; the fire red powder of cinnabar; the complex green of jade, in appearance at once solid and liquid; and even the rare manganese ores, colored like the moods of a geologist confronted with the nightmare of the Franciscan, usually a blank black, occasionally a deeply shocked pink."

Above the foundation of the Marina is a sequence of complex sedimentary deposits laid down by the various natural processes over the last one million years. The sea level retreated four separate times during periods of glaciation, exposing the offshore San Andreas Fault and land as far westward as the Farallon Islands. Streams incised the slight indentation and left their sedentary residues.

In more recent centuries a shallow cove, a tidal marsh, and streams meandering from the uplands produced Bay mud, marsh, beach, and dune deposits while in their separate times Native Americans, Spanish, Mexican and American settlers made their temporary homes by the side of the bay and came to feel the periodic shaking of what they thought was solid ground.

The jellied icing on the cake was applied in the last 100 years, when the vertical history of the Marina District greatly accelerated.

When land became a commodity, its shape was altered by those who wished to buy and sell what became known as "real" estate. Little thought was given to the one natural force that twice within the present century temporarily altered the course of such human transactions.

The Marina District was originally known as Harbor View. The first solid structures were built just Bayward of the Palace of Fine Arts in the 1860s. They consisted of a recreational complex that included baths, bathhouses, an octagonal dance pavilion, a bar and restaurant, and a shooting range. Near the end of the last century heavy industry in the form of shipbuilding, brickmaking, the manufacturing of railroad cars and various metal products, and two coal-gas manufacturing plants moved into the area and dumped their debris into the shallows.

A silver baron's grandiose plan to build an industrial park in the cove stalled after a seawall was constructed in 1893 where the current outer seawall is located. The plan was to fill in the shallow cove that lay behind the wall. Rock was hauled from San Bruno for the seawall and sand was transported from the nearby dunes to partially fill the lagoon which now was almost completely cut off from the Bay.

On the eve of the 1906 earthquake the use of the surrounding land was partly industrial, partly residential and commercial, and partly pastoral. Brick buildings, shops, saloons and woodframe homes were scattered about on higher ground. Chinese tended vegetable gardens in the lower areas. A resident recalled: "After the Chinese gave up the vegetable bed, the low spaces became neighborhood dumps until finally filled in."

Damage from the great earthquake was slight and spotty, probably because nothing of consequence was built on the small amount of fill that had been deposited up to 1906. Frame buildings tilted and foundations cracked. The brick walls of one of the gas plants either collapsed or cracked, the interior wood framework was knocked out of whack, and the brick chimney stack was damaged.

Elsewhere in San Francisco the damage on filled land was quite severe. "The unstable character of the manmade land along the waterfront of San Francisco has long been known," the state earthquake commission noted. Map No. 17 in the Commission's 1908 report clearly delineated the filled areas: present-day Fisherman's Wharf, the Embarcadero, the foot of Market Street, and the South of Market/Mission Creek/China Basin area where various new developments including the Giants baseball stadium were built. Twenty million cubic yards of fill were dumped along the San Francisco shoreline from 1845 to 1920.

An unknown amount of rubble from the 1906 earthquake and fire was dumped into Marina Cove. More prominent mention was made of dumping grounds in Mission Bay and off the Golden Gate. Whatever amount was unloaded, it was dwarfed by the fill deposited behind the seawall to elevate the swampy land for the 1915 Panama Pacific international exposition. Held ostensibly to celebrate the opening of the Panama Canal, the Exposition was actually staged to demonstrate San Francisco's recovery from the earthquake and fire. Ironically, San Francisco celebration of its rebirth set the stage for its next seismic disaster.

During six months in 1912 two giant suction dredges were stationed off the seawall and steadily pumped a carefully monitored mixture of 30% mud and 70% sand into the diminishing lagoon. From a depth of 12 feet below mean high tide the land slowly emerged above sea level. Sand, rocks and soil were imported from inland sites.

Into this new land and the sediment carried deposits that underlay it, more than 15,000 wooden piles cut into 75 foot lengths were driven to provide "earthquake proof" foundations for the many exposition buildings. At a depth of 60 feet of layer of hard green sand and clay, laid down perhaps 10,000 years ago was mistakenly thought to be bedrock.

The 635 acres of Exposition grounds were turned into a fantasyland that set a precedent for later theme parks. The walled city traversed by the Esplanade along the current Marina Boulevard was designed in a hybrid Mediterranean-style, not unlike the present residential structures, albeit on a much grander scale. Elements of Moorish, Byzantine and Romanesque architectural styles were blended in a region that depended upon the redwood tree for most of its construction needs.

A special stucco that imitated the travertine of Rome was developed to enhance the monumental quality of the buildings. The designated colors were warm Mediterranean pastels, the predominant shades of the present Marina. Pink sand was scattered on the surface of the walkways. One building, modeled on the Baths of Caracalla, was so large that it easily accommodated the world's first indoor flight of an airplane.

What went up with a great deal of planning and care came down with alacrity after the Exposition closed — the process of nearly instantaneous creation and destruction being a California oddity. The more valuable materials, like electrical wiring and a few of the structures, were salvaged. Lumber that could not be sold was burned and deposited at the site which was also open to public dumping. The specifications for dismantling the Exposition called for the piles to be cut off two feet below the surface of the ground. More mud was pumped into the low areas to bring the levels of fill up to the terms of leases.

What was first a natural indentation in the shoreline of the Bay became the turning basin for the shipbuilding firm, then the harbor for the Exposition, and finally a small boat marina. The North Gardens of the Exposition became the commons area of the present Marina Green. A spacious development named "Marina Gardens" did not materialize and instead the land was carved up for apartments and single-family residences with 25 foot frontages. In this manner, the modern Marina emerged.

A typical apartment structure built in the 1920s was a three-story wooden frame structure over a ground-level garage. The lack of support on the open first floor weakened the structure. The art deco, green deco, streamlined deco, and zigzag moderne architectural styles of the period predominated. Bay windows were de rigueur. The Marina was a much sought after neighborhood for those who could afford it.

Given the complexity of this vertical history, the unpredictable behavior of seismic waves, and the different tolerances of buildings to shaking, there was no way to know precisely what would occur on October 17, 1989, except that there would be grave problems — even from a quake of moderate dimensions.

The problems were caused by liquefaction and amplification. A University of California report to the mayor of San Francisco stated: "Strong (amplified) ground shaking and soil liquefaction are two separate phenomena, and, unfortunately, the Marina District appears susceptible to both." The uncompacted fill assumed the consistency of quicksand when mixed with the high water table. There were no recordings of the main shock in the Marina, but portable instruments rushed to the scene recorded motions from aftershocks that were amplified 6-10 times greater than what was measured in the nearby bedrock.

History was vomited to the surface in 1989. The bits of charred wood that emerged when sand boils erupted in the Marina were either from the 1906 fire or the leavings of the Exposition. Pieces of imitation travertine also rose to the surface. Startled residents discovered that they were living on a post-Native American kitchen midden.

"I knew my family was in trouble"—

The human reaction to an earthquake is quite complex. Gretchen Wells was both a victim and a representative of the media. Her story, as she told it two weeks later to the California Seismic Safety Commission, incorporates elements of both roles:

"I was on my way to KGO. As a matter of fact I was outside the KGO building ready to report for duty. I was anticipating anchoring the update that evening. And my car started to shake substantially and the whole area started to shake substantially.

I'm the mother of a new baby — relatively new. He's a year old now. And my first impulse was to go to my child. However, I did run up to the second floor of the KGO building and I saw that there was damage. It wasn't substantial but it was enough to prompt me to get home to the Marina.

As I was going home to the Marina there were no cars. There just was no traffic, and I was able to speed through the downtown area, very frightened for my family, but not knowing how bad it was going to be when I reached the Marina because the damage downtown obviously wasn't anywhere near the damage in the Marina. Anyone of you who have seen the damage in the Marina — it's rather considerable.

And I remember getting to Bay and Fillmore and Cervantes which is where the building came down and three died, a baby and a couple. And there was a terrible gas leak and I looked up ahead and there was this building down. And it was just unbelievable because I hadn't seen any damage up until that point.

And that's kind of where the Marina begins. And I knew that I was in trouble. I knew my family was in trouble, and I made my way very quickly in my vehicle toward my home, seeing these buildings just squashed all around me. It was just an incredible experience.

I cover a lot of disasters in my line of work. I'm a hardened newswoman, but not on a personal level. It was just extraordinary what I was seeing. Of course, the more I was seeing as I made my way quickly along, the more fear was developing within me.

And I reached the corner of Beach and Broderick, or Divisdero between Broderick — and that is where I live, and that is where the terrible destruction is, and that is where the fire began. The fire is what I would like to talk about ultimately, just the indescribable shock of being a victim, being there in your neighborhood and seeing this just colossal chaos around you. The helplessness. The disbelief. The people standing around just not able to move. Buildings down everywhere. The gas leaks. It was just a terrible, terrible situation.

I recall trying to make my way through the Cervantes area and there were volunteers already taking charge. There were just one or two police officers. And of course they had their work cut out for them. The volunteers who came to the aid of the various authorities were just extraordinary.

But the smell of gas. I've covered a lot of gas leak stories and this was just a very large gas leak. The danger was very evident to everybody. But no one really responded.

I want to talk about the lack of response. There was a sense that the casualty count had to be extraordinary because of the buildings that were down and because of the fires that were beginning. For about an hour there was no sense of authority. There was no help. Nobody was coming to rescue us. I guess that's kind of what we as citizens anticipate, that someone's going to come and help and rescue us.

I did make my way home finally. I remember I had to go around one person who was lying there, a man, and then there was an older woman who I had to make my way around. She was lying, and someone — there were volunteers to help. Apparently these people had just been pulled out of a building. So I did finally reach my family. They were out on the street. We were reunited."

There were sirens throughout the city, but it was a half hour before Gretchen Wells heard a siren in the immediate area. A lone fire truck from the nearby Presidio Army base appeared on the scene. Finally, the city fire trucks arrived. Gretchen Wells continued:

"And you know, I'm recalling this for the first time. So forgive me if I'm a little bit hesitant. There was a large, four-unit building fully engulfed in flames and the flames were spreading up the block. And there was no water. I want to know why there was no water."

Within minutes of the quake, nearly 35 fires broke out in the city but the five alarm Marina fire quickly became the most serious conflagration.

Even at this reduced level of seismic disturbance, the city nearly came unglued. Planning helped, but the random nature of what failed rendered the best laid plans virtually useless. Improvisation became a necessity. There were good decisions and bad ones.

There was no power. Emergency generators did not start. Phones were inoperable or lines were jammed. Even if callers managed to get through, emergency operators had no firm information.

The following conversation was recorded:

Dispatcher: 911 emergency.

Caller: I need to know, did any — I just heard that something happened to the Bay Bridge.

Dispatcher: I heard that too. But I can't confirm it.

Caller: Do you know if there was anything serious? My dad is supposed to be coming home at this time.

Dispatcher: Hey, I'm not going to scare you. I don't know yet. Okay, I want you to calm down. I don't know, okay? All's I've heard is that the upper deck collapsed.

Caller: (Sharp sob and crying.)

Dispatcher: I don't know if it's true or not, okay?

Caller: (Crying) Okay, thanks a lot.

Radio communications were indecipherable. Computers failed. Fire dispatchers downtown had no idea what was going on in the streets. Fire engines idled uselessly. The smell of natural gas permeated the air. When firemen hooked hoses to hydrants, they found them dry or the water pressure was extremely low. The fire spread. Confusion was rampant.

The regular water supply and an auxiliary system put in place after the 1906 fire for just such an emergency failed. The outdated cast-iron pipes ruptured when the soil liquefied.

One fire truck ran hoses two blocks to the lagoon at the Palace of Fine Arts and drew water from that source. Nearly two hours after the earthquake the City's lone fireboat, the near victim of a declining maritime economy and budget cuts, arrived off the Marina. It was low tide and the Phoenix ran aground, but fortunately it could still pump seawater through hoses to the fire. The effect was immediate and dramatic and by 9:30pm the fire was under control.

More than 80 years later some things were the same, others were different. Navy ships had also pumped water from the Bay in 1906, but to no avail. Normally the wind blowing in through the Golden Gate rakes the Marina District. There was no wind that still October night and that was why more of the city did not burn.

One of the commissioners asked if Wells had ever been told that the Marina was a hazardous place to live. She answered: "We were certainly warned and I was aware that we were on fill. What does that mean to someone who's never experienced a 7.1 shaker? What does that mean to someone who's been living in the City for a long time and has experienced a number of small earthquakes? An earthquake was an earthquake before. Now an earthquake is something very different."

The final toll in the Marina was not the large-scale disaster that Wells had envisioned. Four residents were killed, including a baby. Four buildings were destroyed by fire and seven collapsed. Another 63 structures were declared unsafe for occupancy.

(From 'Magnitude 8,' 1998)

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