Earthquake can strike when you least expect it

Californians know where they were when major earthquakes struck. It’s a way we connect with one another. Two recent earthquakes coincided with significant dates in my personal life, impressing themselves on my memory vividly.

Where were you for the Oct. 17, 1989, Loma Prieta earthquake? That was my daughter’s seventh birthday, and I had gone to the back door to call to her as she played in our San Jose backyard. Maybe we’d go out to dinner to celebrate. As I stood in the doorway at 5:04 p.m., a fortuitous place to be, the house began to shake. In my memory, I see her running toward me, grabbing me to hang on.

Our home was only a few miles as the fault cracks from the epicenter in the Santa Cruz mountains. As events unfolded, the 6.9 quake was the worst since San Francisco’s 1906 earthquake.

Millions watched on television as the Oakland Athletics and San Francisco Giants prepared for Game 3 of the World Series at Candlestick Park and the lights went out. The game was postponed, sending everyone to make their way home on freeways and bridges already closed because of heavy damage. Houses collapsed in San Francisco’s Marina district. More than 6 billion dollars in damage was done, and 63 people died.

Alone with a 7-year-old, we shuddered with every one of the 51 magnitude-3 or greater aftershocks in the first day that followed. I remember it feeling as if the ground were continually growling under my feet.

In 1993, I was in range for the Dec. 22 San Simeon earthquake. My new husband and I were in Kern County Hall of Records in Bakersfield. We had gotten married the day before in San Diego and were headed to Cambria for our honeymoon. We stopped to check some Kern County family records on the way, when the globe lights began to sway over the marble counters at 11:16 a.m. The Hall of Records, built in 1909, was one of the few buildings to survive the previous largest earthquake, 6.2 in 1952. This one registered at 6.5.

Information was scarce right after the quake, but we soon learned that Highway 46 was closed because of earthquake damage. It was open to traffic the following day, so we were able to venture over to Cambria, to my husband’s family’s vacation cabin. The chimney survived the quake, with only a few items knocked off shelves and broken. Our neighbor’s chimney was damaged and eventually was completely replaced.

Californians understand that we live on a cracked landscape, subject to inevitable geological slips that wreak havoc with our lives on the surface. Those who study the rocks, plates and faults beneath our feet learn from every earthquake. The Loma Prieta quake was caused when about 21 miles of the fault ruptured, slipping as much as 7 1/2 feet, between four and 12 miles deep in the Earth. The San Simeon earthquake occurred on what’s called a reverse thrust fault that wasn’t mapped on any of Caltrans’ maps — until that quake.

These seismic calamities get our collective attention in major ways. After the Loma Prieta quake, Congress funded a special appropriation to the U.S. Geological Survey and the National Science Foundation to improve understanding of both the complexity of earthquakes and how society can reduce losses in future earthquakes.

Cambria includes many distinguished people among its residents, including geophysicists such as Don Anderson, who died in 2014. Dr. Anderson was a professor emeritus of geophysics at Caltech and former director of its Seismological Laboratory.

He is considered one of the most influential figures in 20th-century solid-Earth geophysics.

His wife, Nancy, has invited his geophysics colleagues and family friends, Bruce Julian, U.S. Geological Survey (retired) and Gillian Foulger of the Durham University (England) Department of Earth Sciences to visit Cambria in 2016. Dr. Julian has accepted an invitation from Greenspace — The Cambria Land Trust to meet and talk with us about earthquakes.

He has studied the Earth’s shifting plates during his 40-year career and will explain how the forces beneath our feet work — even at times with cataclysmic effects.

This story was originally published January 6, 2016 at 10:20 AM with the headline "Earthquake can strike when you least expect it."