BERKELEY (KPIX 5) — Could low-cost quake detectors become as common as smoke detectors in California homes? A professor at UC Berkeley said he built an alarm himself, for about $100.

Last month’s Napa earthquake was still five seconds from hitting when Berkeley astronomer Joshua Bloom woke up to a warning that said. “Earthquake! Light shaking expected in seconds”

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“I thought, ok. It’s working,” Bloom told KPIX 5.


The device is a small, rudimentary computer that Bloom built as a side project. “This was a hobby,” he said.

Bloom’s device consists of a $35 minicomputer known as a Raspberry Pi, a speaker, a Wi-Fi adapter and an SD card. It relies on sensors all over California to pick up on seismic shaking.

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“Those sensors wind up shaking and send their signals to a central computer,” Bloom said.

Bloom’s device uses the same software developed by scientists at the Berkeley Seismology Lab. It’s called Shake Alert.

“It pushed out an alert and we got about 10 seconds of warning here at the Berkeley Seismo Lab,” scientist Richard Allen told KPIX 5 shortly after the Napa quake.

The device made by Bloom took twice as long to activate, but he’s hopeful this could do what Shake Alert has been unable to do, put their $80 million technology in homes and classrooms everywhere.

“My hope is that knowing that a device like this could exist and people could buy it, and they could just install it themselves. As if they were putting in a Nest thermostat, as easy as that. That people and the public will want to see this get funded,” Bloom said.

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Shake Alert has struggled to find funding despite legislation supporting development. Bloom hopes his device will encourage people to invest in earthquake warning systems.