San Francisco is a tough place live for a lot of reasons.
Sky-high housing prices can make it nearly impossible to find a place. In February, a 1,000-square-foot home with no working plumbing and a pile of rotting mattresses stacked in the kitchen sold for more than $US520,000.
Even tech moguls and startup founders are having trouble finding homes in an area where nearly every spare piece of real estate is gobbled up by the highest bidder. One firm estimated that a home buyer needs to make about $US300,000 a year just to afford a median-priced abode.
But San Francisco isn’t just perilously overpriced: It’s also perpetually teetering on the edge of disaster. On October 18, the city of San Francisco participated in an annual earthquake drill called the Great California Shakeout, a dry run where more than 10 million people across the state practiced a “drop, cover, and hold on” earthquake survival protocol.
None of those people are quite old enough to remember this, but on April 18, 1906, a violent ~7.7-7.9 magnitude earthquake leveled the city into ruins. The minute-long quake ruptured 296 miles of California coastline, sparked three days of fires, and killed 3,000 people, leaving the bulk of the city homeless.
That was just 112 years ago – the geologic equivalent of the blink of an eye.
If earthquakes don’t shake you, consider that the city is literally sinking into mud – and into trash in certain places.
Real-estate woes aside, here are the ways that scientists know living in the Bay Area is not for the faint of heart:
The Bay Area is a veritable smorgasbord of complex fault lines. No less than seven different faults converge here.
The well-known San Andreas Fault is just one of the seven “significant fault zones” the US Geological Survey (USGS) cites in the Bay Area. The others are the Calaveras, Concord-Green Valley, Greenville, Hayward, Rodgers Creek, and San Gregorio Faults.
People who live in the area experience small earthquakes and shakes all the time. But those aren’t the rumbles that scare seismologists.
It’s the bigger, disastrous quakes scientists are really worried about. And they say San Francisco is due for another soon.
In 2007, the USGS determined that there was about a “63% probability of a magnitude 6.7 or greater earthquake in the Bay Area” by 2037.
Estimates have only gotten worse since then. One recent report suggested that there is a 76% chance the Bay Area will experience a magnitude 7.0 earthquake within the next three decades.
Seismologists are most concerned about two fault lines in particular: the San Andreas and the Hayward.
Anything higher than a 7.9 on the San Andreas Fault line, which runs from Mendocino to Mexico, would put “approximately 100%” of the population of San Francisco at risk, while a 6.9 quake from the Hayward Fault could spell trouble for nearly everyone who lives and works there, according to the city.
At least 300 buildings sit directly on top of the Hayward Fault, and another two million in the San Francisco Bay area would also be under threat if a big quake hit the region.
The USGS predicts that at least 800 people would be killed and 18,000 more injured, if a hypothetical 7.0 hit nearby Oakland, California.
The scientists warn the threat of a future earthquake like that “is real and could happen at any time.”
Some geologists are predicting that 2018 will be a banner year for quakes around the world.
The Earth is turning a little slower than usual right now, which puts extra squeeze on tectonic plates and may mean more high-magnitude shakes are on the way.
Certain neighbourhoods in the city are built on less-than-rock-solid heaps of trash.
Old 19th-century trash that was dumped out to widen the city could quickly level the bottoms of many homes during a big quake. It already did once in 1989.
Experts estimate that places like the Marina neighbourhood, pictured above, would today be 50% destroyed by anything higher than a 7.0 magnitude earthquake on the San Andreas Fault.
And many of the cities tallest downtown buildings are sitting on ground that could easily liquify during a big earthquake.
The New York Times recently estimated that more than 100 of the city’s tallest buildings (higher than 22 stories) have been built in areas with a “very high” chance of liquefaction in an earthquake.
But San Francisco’s quake threat doesn’t stop at the shore. Tremors could hit the city from the sea, if powerful tsunamis rush in from places across the water like Russia, Alaska, or Japan.
That’s less likely than a Californian earthquake, because typically, tsunami waves aren’t super serious once they reach San Francisco’s shores. According to the city, most of the tsunamis that hit the Bay Area from Alaskan earthquakes are less than 1 foot high by the time they make landfall.
But there’s still a chance that a tsunami moving in from the Cascadia subduction zone (which stretches from Canada’s Vancouver Island into Northern California) could come into the Bay Area at more than 16 feet high, UC Santa Cruz earth sciences professor Steven Ward told KQED.
Earthquakes can also unleash tough-to-control fires, as they did here in 1906, covering much of the city in flames and smoke.
Thankfully, the city itself isn’t perpetually threatened by wildfires, like much of the rest of the state. But the nearby vineyards of Napa Valley did not escape the 2017 wildfire season unscathed.
In October, more than 3,500 homes, buildings, and other structures were reduced to ash. At least 31 people were killed.
Many people in San Francisco took to wearing masks so they wouldn’t have to breathe the smoky fumes wafting in.
In the nearby East Bay, a 1991 “firestorm” triggered by a grass fire killed 25 people.
East Bay resident Will Wright, who had a near-death experience when his home burned to the ground, was inspired by the tragedy to create the wildly popular game “The Sims,” according to local news site Berkeleyside.
Shaking aside, the region is bracing to see more water coming in over the next several decades.
The water level in the Bay Area has risen 8 inches over the past 100 years.
Researchers estimate that by 2100, the sea will rise anywhere from 2.4 feet to nearly 4.5 on the California coast, putting the headquarters of Silicon Valley companies like Facebook and Yahoo underwater, if nothing more is done to mitigate the effects of climate change.
In 2016, the city of San Francisco estimated sea levels there would rise 66 inches by 2100. That’s 5 1/2 feet.
The sea change won’t come cheap. At least $US62 billion in property and infrastructure is at risk.
That’s the calculation with just a modest 4 feet of sea level rise.
But the flooding problems don’t end with seawater. San Francisco is also sinking into the ground at a rate of about 10 millimetres a year.
The natural caving-in process at work is called “subsidence,” and it’s happening because the city is built on heaps of trash and Holocene-era mud that’s slipping away.
And more more frequent storms could make landslides and flooding more common.
“Severe storms can cause landslides, coastal flooding, and stormwater ponding,” the city warns. Scientists predict we’ll see many more of those kinds of events in the coming years, as more “surprise” and potentially irreversible climate events crop up around the globe.
California’s seemingly never-ending series of droughts is also a concern for San Francisco Bay Area residents.
Still, supplying Californians with enough water to live is increasingly becoming an expensive problem. The Pacific Institute estimates that municipal water costs in California metro areas rose at two to three times the rate of inflation between 2000 and 2010.
With more extreme climate shifts and heat waves on the way, San Francisco will have an unusual problem on its hands: a lack of air-conditioners.
With extreme weather events and heat waves on the rise around the world, people in San Francisco may have a tougher time than other Americans finding relief from scorching temperatures at home, at least in the near future.
According to the 2011 housing survey of the US Census, “the Bay Area had the lowest percentage of housing units with central air-conditioning (10%) of any region in the country,” the San Francisco Business Times reports. That compares with 66% of people nationwide who said they have central air at home.
If you decide to stick around the Bay Area, it’s probably time to make sure you’re prepared for all these various disasters with a well-stocked emergency kit.
The San Francisco Department of Emergency Management suggests having enough water, nonperishable food, and flashlight batteries on hand to last about three days. Because in San Francisco, you just never know.
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