How far do you live from Berkeley’s tsunami zone? See the hazard map.

On March 11, 2011, a tsunami surge pressed into the Berkeley Marina, causing $158,000 of damage to docks and boats.

Above: The state’s new tsunami hazard map tells you if you’re in the danger zone. Yellow shading shows the hazard zone.

Learn more about what to do before, during, and after a tsunami in Alameda County.

The city reported the damage in its 2019 “Hazards of Concern” report, one piece of a broader effort by the Berkeley Fire Department to help the city prepare for natural disasters.

“Tsunamis generally impact the Pacific Coast of California, and reports of tsunamis entering the San Francisco Bay are rare,” according to the report. “Tsunamis, or seiches as they are called when they occur within an enclosed body of water, can also be generated within the Bay by the Hayward fault. The 1868 Earthquake on the Hayward fault is reported to have created a seiche within the Bay. It is unknown whether the seiche impacted the City of Berkeley.”

Because they are so rare, it’s hard to predict how much damage a tsunami might cause in Berkeley, the city wrote. But it can be significant, as 2011 showed.

“Buildings affected by tsunamis can be damaged by either the inflow or outflow of water. Tsunami damage to coastal infrastructure can release complex debris, crude oil, various fuel types, and other petroleum products, cargo, and other pollutants into nearby coastal marine environments and onshore in the inundation zone. Fires often occur within the inundation zone. Tsunamis also damage roads through erosion,” according to the report. 

Deaths are also possible, if people are unable or choose not to leave hazardous zones, and “Injuries and illness can result from contact with tsunami surges.”

In December 2010, just months before the Tohoku earthquake and tsunami would leave more than 25,000 people dead or missing along Japan’s northeastern coast, the state of California’s Emergency Management Agency put out its first tsunami inundation map for the Bay Area. The map, designed to aid in emergency planning, was based on existing sea levels and land elevation and showed how far inland surging seawater might go in a worst-case scenario.

That worst-case scenario was based on what happened March 28, 1964, when a magnitude 9.2 earthquake killed 12 people in Anchorage, Alaska, and leveled much of its downtown commercial district. Four hours later, according to the California Geological Survey (CGS), multiple seawater surges up to 21 feet tall swept into Crescent City, California, not far from the Oregon border.  

“For most of California,” CGS said last year, “the biggest tsunami threat would result from another huge earthquake in the Aleutian Islands.”

In March 2021, as part of a 10-year retrospective on the Japan earthquake and tsunami, the California Geological Survey, the California Governor’s Office of Emergency Services (Cal OES), and others released a new version of its tsunami hazard map for three California jurisdictions. Fortunately for Bay Area residents, Alameda County was one of them. (Updates for other counties followed and that work is ongoing.)

The 2021 update, which was based on new data and better computer models, extended the Tsunami Hazard Area in northwest Berkeley inland by four or five blocks, in some places as far as Sixth Street, the Geological Survey reported. “In a worst-case tsunami, sizeable areas of Alameda, Oakland, and Berkeley could be flooded up to an 18-foot elevation.”

Read more about the how experts plan for tsunamis and predict the damage they can cause

According to the map, the hazard area in Berkeley extends to Fifth or Sixth streets from about Delaware Street to the Albany border. From Ashby Avenue up to Delaware, the hazard zone mostly follows the railroad tracks on Third Street but, closer to Ashby and University avenues, the zone extends slightly farther east.

Experts note that the hazard maps created by the state are based on limited data which results in a certain margin of error. But it’s still important, as the city works to plan for disasters, to be aware of what could one day come. 

According to those models, as with the large Aleutian Island quake scenario, the initial tsunami surges “would reach the Bay Area and Monterey in about five hours.” As was indeed the case Jan. 15, it may take perhaps an hour for the National Tsunami Warning Center to issue a warning. Then local authorities need time to determine what their potential risks may be. 

The bottom line, according to CGS, is to “move inland as soon as possible” if you’re near the coast and “feel strong shaking from a local earthquake or get an official notification to evacuate.”

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