Development in the years following the 1989 Loma Prieta event has concentrated heavily in the area between the San Andreas and Hayward faults. Epicentral location for the Loma Prieta Earthquake shown with the purple star. (Sources: USGS and RMS Exposure Source Database) Development in the years following the 1989 Loma Prieta event has concentrated heavily in the area between the San Andreas and Hayward faults. Epicentral location for the Loma Prieta Earthquake shown with the purple star. (Sources: USGS and RMS Exposure Source Database)

Thirty years ago on October 17, 1989, California’s central coast was hit by what is now known as the infamous “World Series earthquake,” officially dubbed Loma Prieta. The 6.9 magnitude earthquake occurred during Game 3 of the World Series between neighboring Bay Area teams — the Oakland Athletics and the San Francisco Giants — and was documented during the game’s live television broadcast.

The Loma Prieta earthquake wound up costing $6 billion in economic losses and $902 million in insured losses.

On the 30th anniversary of the famous quake, global risk modeling and analytics firm RMS calculated that if Loma Prieta struck again today in exactly the same place, it would cost $38 billion in economic losses and $4 billion in insured losses.

Behind the $32 billion cost increase

The vast change in the risk landscape between 1989 and 2019 is due to a number of reasons. For example:

  • Increased productivity: In 2017, the San Francisco Bay Area was the 19th largest economy in the world with a GDP of $748 billion. This means more buildings in the same area, increasing the likelihood of substantial damage. If the Loma Prieta event were to happen again today, the headquarters of six of the world’s ten largest technology companies (named by Forbes) would experience strong shaking (MMI greater than 6).
  • Increased protection gap: With a relatively low insurance penetration of about 10%, a significant portion of homes are not adequately protected and will take longer to rebuild, which will disrupt communities and the region’s economic output.
  • Increased population: Since the event, the eight counties most heavily affected (San Francisco, San Mateo, Santa Cruz, Monterey, San Benito, Santa Clara, Alameda, and Contra Costa) have added almost two million residents, a growth of nearly 35%.

While an identical earthquake to Loma Prieta will not occur again, RMS projects that the likelihood of an earthquake of the same magnitude (Mw 6.9) or higher hitting the Bay Area within the next year is very high: 5.3%.

The RMS report models four different earthquake scenarios of the same magnitude as Loma Prieta (Mw 6.9) impacting different communities around the Bay Area.

The scenarios are detailed in the graphics below, which outline the projected economic losses, insured losses, and the number of casualties that a similar-sized event could cause today.

Economic and insured losses for each scenario compared to the modeled 1989 Loma Prieta loss based on present exposure. The losses are shown in USD billion. (Photo: RMS) Economic and insured losses for each scenario compared to the modeled 1989 Loma Prieta loss based on present exposure. The losses are shown in USD billion. (Photo: RMS)
Modeled range of fatalities and the day-time weekday average for the scenarios and the 1989 Loma Prieta Earthquake. (Graph: RMS) Modeled range of fatalities and the day-time weekday average for the scenarios and the 1989 Loma Prieta Earthquake. (Graph: RMS)

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