Hundreds of earthquakes — from very small (magnitude less than 1) to minor (magnitude 4.0 to 5.0) occurred near the Salton Sea last week. Again demonstrating his prescience for disaster, Mike Feyder, head of the local Mountain Disaster Preparedness group, had already scheduled a community meeting to hear a speaker from the California Institute of Technology’s Office of Earthquake Programs.
The bay of the Idyllwild Fire Station was filled Saturday with people who came to learn more about quakes and preparing for them. While Margaret Vinci, head of the earthquake program at Cal Tech, assured the crowd that the swarm of quakes south of Idyllwild was not necessarily a precursor for the “big one,” she did emphasize the need to be prepared if it occurs.
“The more and better prepared you are, the better you will survive,” was the first message Vinci delivered.
In his comments before Vinci spoke, Idyllwild Fire Chief Patrick Reitz reinforced the need for local preparation. “The Salton Sea is a wake-up call for us,” he said. “We need you all to be prepared because we can’t get to everyone immediately.”
Idyllwild and most of the Hill rests on a granite base. Tremors will move through this terrain quickly, which reduces the probability of major damage compared to the soft soil under Los Angeles. However, the danger is the numerous boulders and rocks along and above the local highways. The undulating ground can easily dislodge these boulders, which could damage and block highways similar to when the boulder blocked traffic on Highway 243 between Idyllwild and Pine Cove in January, Vinci warned.
Earthquakes are just one of many potential disasters making California a multi-hazard state. The secondary effects of quakes — fires, road closures, pipeline disruption and more — can create the damage.
Quakes are the biggest natural risk throughout the world. More than a thousand quakes occur each day, Vinci said. The U.S. Geological Service reported nearly 800 quakes in the past month, just in California, and more than 7,000 in the past year.
“In the U.S., the most are in Alaska, and California is second,” Vinci said. “We are the most at risk because of our population and infrastructure.”
If one hears the earth rumble and then feels the shaking, the advice is “Drop, cover and hold on.”
First get down, a high-magnitude quake is powerful enough to knock a human down. As you are dropping, find cover, for example, a table.
One of the dangers of a quake is dislodging items from walls or shelves, which could injure someone. Two years ago, during a 6.0 quake in Napa Valley, one death occurred. The victim had fallen asleep in his house and the quake dislodged his television from the shelf. It fell and hit the man on the head, causing his death.
So, one of the preparations for a quake is to ensure that items above head height are secured and unlikely to fall and injure someone.
Also as you cover, hold on to the location. The shaking could cause something, such as a table that is not secured to the ground, to move and leave you unprotected.
There are more than 300 faults in California. The Hill is just west of the San Andreas fault, which is the largest. But the San Jacinto and Elsinore faults are closer and just west of here. The Easter 2010 quake in Baja, Mexico, actually “uploaded more stress on the Elsinore and San Jacinto faults,” she said.
A magnitude 6.0 or greater quake on the San Jacinto fault cannot be unexpected. Three have occurred in the past 100 years. “Quakes of magnitude 2, 3, 4 or 5 do not relieve stress, it has to be 6.0 or above,” she said.