New toolkit helps citizens prepare for earthquake survival
MENDOCINO, CA » On April 3 and 4, Rio Dell, located about 108 miles northeast on Highway 101, experienced three earthquakes. On April 3, two earthquakes registered consecutively at 4.1M and 3.9M. On April 4, an earthquake of 2.9M followed. Suppose a cell phone user in that area did not receive any text warnings. In that case, the California Office of Emergency Services (Cal
OES) does operate an alert system available to anyone on the West Coast. Although drought and wildfire dominate the natural disaster news, earthquakes need not catch Californians so off guard that survival isn’t likely.
The San Andreas Fault extends along the California coastline for about 750 miles. It borders two tectonic plates, the Pacific and North American Plates. Constantly grinding against one another, the Pacific Plate moves northwest while the North American
Plate moves southwest. This faultline reaches southern Mendocino County on land via Fort Ross in Sonoma County, passes through Manchester, and then travels along the coast of Mendocino County to Point Arena. Here the fault line veers offshore and passes underwater nearby Mendocino and Fort Bragg. The fault swings back onto the coastline south of Shelter Cove, North of Westport. The likelihood of a significant earthquake close to Fort Bragg is a given, not a mere possibility.
The San Andrea Fault is extremely active and has been the cause of many significant earthquakes of large magnitude. This past April 18 marked the 116th anniversary of the deadly San Francisco earthquake of 1906, which had a magnitude of at least 7.8. On the magnitude scale, 8.0 represents an earthquake powerful enough to destroy nearby communities completely. The 1989 Loma Prieta earthquake in the Bay Area
registered at 6.9, classifying it as a major earthquake. Both quakes were felt in Mendocino County since the shock waves can travel up to 300 miles from an earthquake’s epicenter.
Unlike tsunamis, earthquakes cannot be predicted. However, the technology exists for alerting the public to a nearby earthquake shortly before we feel the shocks. This technology is being constantly improved and updated to shorten the time between earthquake detection and accurate public alerts. Cell phone users can already receive notice of earthquakes from FEMA’s Wireless Emergency Alert (WEA). The Amber Alert system is a prominent part of it. Millions of cell phone users subscribe to this federal alert system for various warnings. Unfortunately, this system’s earthquake alerts do not make use of current technology that is more precise in assessing quakes and is faster to inform the nearby public.
If phone settings are adjusted to receive emergency alerts, users can download the free service, MyShake App, in English or Spanish, at the Apple App or Google Play stores. Android phones are already automatically subscribed to Android Earthquake Alerts, which uses the same technology as the MyShake App. The MyShake App provides audio and visual warnings for a magnitude 4.5 or higher and Modified Mercalli Intensity III (weak) shaking. WEA, on the other hand, sends alerts for greater magnitudes and intensities.
The science behind this alert system relies upon basic earthquake behavior since earthquakes send out two different types of waves. Ground sensors detect P-waves, the first type to occur. That data is transferred to an earthquake alert center which determines the location and size of the quake. A continually updated message is immediately sent to users, and it may arrive either before, during, or after shaking begins in your area.
The second set of Swaves
and surface waves follow the P-waves. These waves are the ones that cause damage. In general, how close seismic sensors are to each other, how quickly the data can move, how deep it started in the earth, and whether it moved through sand, solid ground, or bedrock determines the length of the warning. The closer you are to the epicenter, the faster you receive an alert.
An earthquake early warning is not a prediction. The purpose of the alert is to give people precious seconds before shaking starts to “Drop, Cover, and Hold On.” You may receive a warning when there is no earthquake, although this should be rare. This technology will improve as all agencies and partners continue to collaborate on finetuning it along with the California Integrated Seismic Network (CISN). This network uses cell phone towers and a statewide microwave system which supports the state’s 911 system and the radio communications of many state and local agencies.
Cal OES also has recommendations for advance preparation for earthquakes. These can be downloaded from their website, caloes.gov, in the form of posters or booklets to assist the public in the practical steps to take before, during, and after a quake. The website also offers a magazine, “Living on Shaky Ground,” published by CSU Humbolt, which is geared to the North Coast region. The information allows the reader to think through all the decisions that come into play after this type of disaster. Especially helpful are two checklists that can be downloaded, “Seven Steps to Earthquake Safety” and
“Emergency Kit Checklist.”
The “Seven Steps” include where to go in your house or place of business for the safest protection, what to do if you are driving, why you shouldn’t use phone service afterward to locate family members or friends, why you will need cash in small bills, what to keep in an emergency kit, and also remind you to consider your pets. To address the reality of financial hardship, the website also advises the purchase of inexpensive earthquake insurance, which is not included in homeowners’ policies.
Also included are various toolkits and resources designed for specific sectors of the state’s population such as business, medical, utilities, K-12 Education, first responders, and more. These are easily accessed at https:// earthquake.ca.gov/getprepared.
Every county has a state OES office, usually located with other county government buildings. Its purpose is to coordinate needed response services with the county government and other local agencies during and after disasters. In Mendocino County, the state OES office is located at 951 Low Gap Road, Ukiah, CA. The office phone is 707467-6497, and the website is www.mendocinocounty. org/government/executiveoffice/office-of-emergencyservices.