Two strong earthquakes have struck Southern California in just 36 hours; one occurred in the morning of July 4th with 6.4 magnitudes that cracked the roads urging locals to flee for safety. When the region thought the tremble was finally over, another earthquake hit after a day and a half with a powerful 7.1 magnitude.
The two quakes tallied no deaths or significant injuries, but the intensity was strong enough to break down store shelves and sway buildings. The tremor was also felt by other states, including Phoenix, Arizona.
Earthquakes in this part of California are not unexpected, but the two most recent seismic activities are the largest that have struck in decades. These events allow scientists to look at the complex geology of California and explain the quakes that hit the Eastern California Shear Zone. The said zone is an area of San Andreas Fault where the Pacific Plate grinds against the North American Plate to the east. Here, the plates grind past each other horizontally with a rate of 2 percent inches per year. And a slight motion can lead to a few smaller shocks and tremors.
However, the infamous fault is not a single line but a network of faults that go along California through the areas like Los Angeles and San Bernardino counties.
The earliest known occurrence of Earthquake in California was documented in 1769 by the Spanish explorers and Catholic missionaries, as they traveled northward from San Diego along Santa Ana River near the present site of Los Angeles. Since then, records were sparse, and other information for earthquake occurrences only came from ship captains and explorers.
But the 1868 Hayward incident caused more significant damages to San Francisco Bay Area along Santa Rosa in the north to Santa Cruz in the south. Scientists that time knew how serious the threat was to the people, but seismology was still on the developing stage while technologies for seismic activities were not yet recognized. When the 1906 San Francisco earthquake hit the city and killed 3,000 people, the U.S Government saw the problem including lack of earthquake preparedness program and governing agencies. So it established the United States Weather Bureau along with the United States Geological Survey to write reports and research on seismic activities.
The 1906 incident paved the way to the creation of the state’s first monitoring program online at the University of California by Professor Andrew Lawson. It was in the late 1920s when the Richter Magnitude Scale was developed at the Caltech Lab in Pasadena to observe earthquake through seismometers. The device became a champion in predicting possible earthquakes in the area, which also gave birth to more advanced tools intended for studying other seismic activities.
Today, scientists in USGS maintain a series of fault and volcano monitoring instruments, where data from these tools are transmitted via satellite, radio, and telephone telemetry. Aside from that, there are Earthquake-savvy smart sensors that can be installed directly on the machines itself and can close down other hazardous equipment once vibration is detected. This device is called Omron D7S Seismic Sensor, which can also map the seismic intensity and provides information on the risk of collapsible buildings.
In 2014, Mexico introduced the earthquake warning device called SASMEX (Seismic Alert System of Mexico). It is an earthquake warning network that has been used by other countries since 2000. SASMEX alerts send warnings and relay vibration data to a microcontroller and local alarm in a compact unit. The sensors can also send data using the internet and can be transmitted to other devices to alert users in the coming earthquakes.
While these devices are helpful in the prediction of future earthquakes, mobile apps are also in demand nowadays. One example is a free app for Google Android Smartphones called “MyShake” from the Berkeley Seismology Lab, which designed to detect earthquake shaking with the use of accelerometer sensors in mobile phones. The app sends information to a central processing center that confirms the location and possible magnitude of the quake. It can be used to tell users with past and most recent earthquakes around the world, thus giving them ideas about future seismic activities.
After the quake in the US’ West Coast last Friday, scientists are estimating that California will be facing another earthquake in the coming weeks and another five shortly as magnitude seven usually includes aftershocks that last for years. This prediction becomes possible due to the availability of technologies that forecast seismic activities in the area.
With the help of these devices, government and its people will have enough knowledge about natural calamities like earthquakes to prevent further damages and fatalities. In addition to the loss of life, earthquakes create financial turmoil. When a seismic activity happens, countries which build first-generation infrastructures and establishment can be largely affected by losing billions in the process. But with warning devices that alerted everyone, all of these can be prevented.