Preparing Santa Monica for the next big earthquake

Preparing for the Next Quake

Last week’s SMa.r.t. column was about sustainability. This week we look at another part of sustainability: surviving inevitable crises that rarely occur but have a disastrous impact. For example, the San Andreas fault creeps about 2 inches per year but in a large earthquake could move 12 feet in a minute. Likewise, the climbing ocean levels may take decades to rise one foot, but a tsunami can raise the sea level 30 feet in 3 minutes. Recently, earthquakes above magnitude 6 occur in the Los Angeles basin every 23 to 38 years. It has now been 21 years since the last big quake in Northridge. This 6.7-magnitude earthquake killed 60 people and severely damaged the Northwest quadrant of Santa Monica. We are now entering a period of increasing statistical probability of a significant seismic event.

We have seen enough disaster movies to know what to expect in such an event. The first three days will be chaos, including fires, building collapses, overwhelmed first responders, hospital triages, and everyone in survival mode. Afterwards, the survivors will be “camping” in a ruined city for up to a year before water, phone, gas, power and food supplies are fully restored. During that period some reconstruction will occur but, given the shortage of skilled labor, financing and the supply chain interruption, reconstruction could continue for up to 10 years. A decade later and New Orleans, New Jersey and Long Island are still under reconstruction.

While individuals are responsible for their own initial 3-day survival (water, food, general repair), there are things we can do as a city to minimize the “camping” phase of the post-quake recovery.

1. Identify where and how to house residents whose homes are deemed to be uninhabitable. No one knows how many buildings will be unlivable after a large quake, but using the San Vicente corridor as a guide, after the 1994 quake it lost roughly 5 percent of its structures. If that same percentage were applied to Santa Monica, about 4,500 Santa Monicans might need emergency housing. Since most residents will want to stay in Santa Monica, the city should plan now for the required open space to park the tents and FEMA trailers and the distribution of life neccesities. Also it should take stock of how many hotel rooms, vacant apartments, empty classrooms and short-term rentals might be available for emergency housing. Abundant open space in our already dense city is not just a quality-of-life issue, but possibly a source of survival in a worst-case scenario.

2. Do not build over 4 stories. Low-rise buildings are easier to escape from in the initial quake and fires as well as easier to live in without power. After the initial shock, we can expect a slow and partial power supply restoration to different parts of the city over a year with intermittent brown outs. During that time, many senior citizens who can’t do stairs could become prisoners in their own apartments. Likewise, parents carrying small children and groceries may not be able to make it up long, multi-story stairwells. Finally, mid-rise businesses (e.g. hotels) relying on elevators could become (barring generators) uninhabitable. As a minimal standard we could require stairwells and halls to have windows or skylights; and buildings to have enough solar collectors to continually illuminate their interior halls and stairwells. In fact, an abundance of solar collectors combined with battery backups increase any building’s odds to keep functioning during the loss of the power grid.

3. Lots of bicycles. Cars parked in deep subterranean parking lots could be trapped because of the no power for ventilation and garage gates. Likewise, gas stations may not be able to pump gas consistently and traffic and street lights may be down. Bicycles might be the transportation mode of choice for many and would have the added advantage of being able to maneuver around piles of debris and broken pavement. Fortunately, our City has a growing bike path system, and the new zoning code will, as new buildings are built, begin to provide more bike parking. Finally, getting the city’s bikeshare program fully stocked and integrated with that in Los Angeles in a timely manner should be part of the City’s quake survival strategy.

4. Hardening our existing buildings. Building design and seismic technology has progressed substantially in the last two decades. One of the disquieting things we have learned is that large quakes can easily generate 1g forces, or 5 times the forces that typical residential buildings are designed to withstand. While most buildings on paper could not survive a 1g jolt, in real life, the interaction of many repetitive elements and short quake duration might make it possible to survive such an extreme quake. In such cases, most buildings would not collapse completely, although they might still be a total loss. So every opportunity must be taken to upgrade our existing buildings to reduce the possibility of a total collapse. After the 1994 quake, the city did an initial structural review of all its buildings but has never published its results. It is time to publish that list and alert owners so that they can begin the process of upgrading their buildings to potentially save lives.

5. Water is the real choke point. People can live without power, but only three days without water. There is a high probability that a large earthquake on the San Andreas fault could cause us to lose about a third of our water that currently comes from two aqueducts that cross the fault. In addition, new homes that use tankless water heaters will lose that built-in water reserve. A well strapped 50- to 60-gallon tank water heater can provide a family of four about two weeks of water at the survival rate of 1 gallon per person per day. It is unclear if our water system of well pumps and sewer pumps can survive a power cut off or intermittent power supply not to mention the possible initial 1g jolt. As the city adds more residents and businesses, the need to be able to provide them water in an emergency becomes increasingly difficult. Even if the city could fix the innumerable quake ruptured water mains, if the water is not there, we have painted ourselves into a corner. The current upgrading of the water system infrastructure should be skewed toward survivability before additional growth is programmed. The sooner we can get to water independence from our own wells, the better.

6. Early warnings. Finally, while quake prediction is a long way off, functioning early-warning systems are available today. Relying on the different speed of seismic waves, sensors can give a 10- to 30-second warning before the really damaging waves arrive at a building. That warning interval, while not large, may allow people enough time to safely exit buildings and elevators, garage doors, stop elective medical procedures and take countless other life and property saving actions. While costs of such systems are not precise, costs of $200-$300 million have been estimated to cover California with sensors (plus $5 million per year to maintain them). These are small prices ($10/resident) to pay given the potential to save lives. We should contact our public representatives and lobby them to install such a system over the entire state now.

Our City has to be both sustainable and survivable. Survivability is sometimes called resilience: the ability of a City to bounce back from a catastrophe. These are not pleasant things to contemplate, but to ignore them would be much worse. Resilience is something we have to build in today. We have been fortunate to have had a 21-year respite from a major quake, but as each day passes, the odds increase that it will be here soon. Let’s be ready.

Mario Fonda-Bonardi AIA, for SMa.r.t. (Santa Monica Architects for a Responsible Tomorrow)

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