If the Big One hits, everyone knows the drill: Duck, cover and hold.
But what about the Big Wave? As in, tsunami?
“I’d grab my purse and I’d leave all my crapand I’d get in my Range Rover and I’d be out of here,” said Mala Quatman, 60, of Danville, who was enjoying a recent sunny day on Alameda Beach where the estuary waves barely lap the shore.
Cya Nicole, 22, of Oakland, who was painting at Lake Merritt with her dog Simba, said she’d head to the roof of her apartment building, just a few minutes’ walk away, because it’s in a safe zone.
“I’ve seen enough movies to know that you should stay calm,” Nicole said. “You’re not going to get where you want to go if you’re panicked, if you don’t keep a straight head.”
Quatman and Nicole were interviewed one recent Friday at two of the numerous Bay Area spots identified by newly released California Geological Survey maps as tsunami hazard areas.
The bad news is that tsunamis are somewhat common occurrences, but the good news is that the scariest ones — those that tower 25 to 30 feet upon entering the Golden Gate, rush across the Bay, crash onto shores and swallow up city blocks — likely would come around only once every 1,000 years or so. Of course, that 1,000-year event could come any time.
“Tsunamis happen a lot. It’s kind of surprising. But most of the time they’re only picked up on tide gauges because they’re small,” Rick Wilson, a senior engineering geologist at the California Geological Survey, said in an interview.
But while there’s only a 5% chance the Bay Area will see a massive tsunami over the next 50 years, people still need to plan as if tomorrow might bring the millennial event, Wilson said.
“The better informed the public is, the more likely they are to save their lives and their families’ lives,” Wilson said, “and that’s what we want.”
When major tsunamis hit, the damage can be catastrophic. The most destructive one to reach California in modern history happened on March 28, 1964, according to the California Department of Conservation. During that event, “several surges reaching 21 feet high swept into Crescent City four hours after a magnitude 9.2 earthquake in Alaska, killing 12 and leveling much of the town’s business district.”
More than 150 tsunamis have hit California’s shores since 1800, but only a few in addition to the one in Crescent City have had significant impacts.
Most recently, the ripples from the 2011 Tōhoku earthquake and tsunami in Japan — which killed more than 18,000 people there — caused about $100 million worth of damage to California ports and harbors, including Santa Cruz, and killed one man.
The Geological Survey has been updating tsunami hazard maps since last summer to account for a millennium event, including the maps of Bay Area counties in recent months.
“The Japanese had actually only planned for 100-year to 500-year historical events, and it turns out they got their 1,000-year event. For us, that was kind of a call to look and investigate and see what a 1,000-year event would look like for California, to protect its coast,” Wilson said.
The updated maps are based on a “worst-case scenario” such as a magnitude 9.3 earthquake near the Aleutian Islands of Alaska. A temblor that powerful could shoot a miles-long series of huge waves traveling at jet speed toward the Golden State’s coast, arriving in about five hours.
“That may seem like a lot of time, but it will take an hour or so for the National Tsunami Warning Center to issue a warning to California and then additional time for local authorities to determine whether an evacuation is necessary, ” Wilson cautioned. “The bottom line is, if you’re near the coast and feel strong shaking from a local earthquake or get an official notification to evacuate, move inland as soon as possible.”
Though waves three stories high as they enter the Golden Gate probably would lose some size and steam as they advance farther into the Bay, they could still land as much as 12 feet above the normal waterline, inundating western areas of Oakland, Berkeley and Richmond, as well as San Francisco’s Marina District, according to Staci Morrison, a spokesperson for the Department of Conservation.
Treasure Island would be covered and most of Alameda would be flooded, save for a small central portion of the island.
Certain spots along the Bay would get wiped out while others would be spared. All of Oakland International Airport would go under but San Francisco International should escape in good shape except for some wet runway edges.
Sections of interstates 880, 80 and 580 through parts of San Leandro, Oakland, Emeryville and Richmond could get soaked.
The Warriors’ $1.4 billion Chase Center in San Francisco would be flooded, as would the Giants’ Oracle Park and much of the waterfront north of there.
And if the Oakland A’s end up building a $1 billion waterfront ballpark at the Port of Oakland’s Howard Terminal, it would also be hit with powerful waves.
The tsunami likely would dissipate as it heads farther south toward southern Alameda County, San Mateo County and Santa Clara County. Around the bay, how high and far the surge reaches inland would be affected by how low the land is, Wilson said.
San Jose International Airport would stay dry since the waves should have shrunk to only a couple of feet by the time they reach the South Bay. The Googleplex in Mountain View and Yahoo’s headquarters in Sunnyvale should emerge unscathed. Facebook’s campuses in Menlo Park appear in the maps to lie just outside the potentially wet areas.
But, Wilson noted, “Because it’s a strong moving current, even if it’s only a foot high, it’ll knock you down, and (tsunamis have) killed people even at one foot,” he said.
And if that current is coming, walking away from danger is better than trying to drive away and getting stuck in traffic when a tsunami hits, he noted.
Tyler Everett, 33, of Berkeley, who was eating shawarma wraps on the sand of Alameda Beach with his friend Jeannine Koewler, 33, of Seattle, worries that chaos would ensue with word of an approaching tsunami.
“I bet you most people would hop in a car. If that were to happen right now, we’re jumping in the car. I’d probably go back to Berkeley. I’d get my cat,” he said.
Koewler joked that indecision might doom her, even with hours of warning time.
“Honestly, I would die. Because I would go back to my home and be like, ‘What do I get?’ And I would spend the next five hours packing,” she said.
Although Wilson said the new massive seawalls being built at Foster City should fend off a big tsunami, a promontory at Shorebird Park near where 59-year-old Prakash Das walks his dog along Beach Park Boulevard might get flooded.
But Das would just have to walk about a block west to safety, according to the state maps, so he likes his odds of surviving.
“I’m kind of a math guy,” he said.
