California Earthquakes: Why Do They Happen So Frequently And More

For children growing up in California, earthquakes are a common occurrence.

Did you know that California is one of the most seismically active states in the United States? But why do they happen so often in this state?

California is located along the San Andreas Fault, where two plates collide. So, it is prone to earthquakes. There are dozens of earthquakes each year, and while most are too small to feel, some can be damaging or even deadly. Read on to explore the history of earthquakes in California and the potential dangers they pose to the residents.

Frequency Of Earthquakes In California

An earthquake is a very frequent occurrence in the state of California. However, most of them are pretty small and not felt too strongly. Read on to know how frequent quakes of different scales are.

As per B. Gutenberg and C. F. Richter, it is said that the southern Californian region inclusive of Owens Valley experiences 0.5% of the world's seismic activity. However, most of the quakes that happen in California go unnoticed because they are small earthquakes of low magnitude.

Currently, California experiences two or three moderate level quakes each year, with a magnitude of 5.5 or higher. These earthquakes are large enough to cause damage but are not entirely disastrous in most cases.

Over the span of 1921-1934, the region of California and Nevada experienced around five major earthquakes. These shocks were pretty large, all measuring at magnitude 7 or higher.

The quakes happened in 1922, 1923, 1927, 1932, and 1934. The largest magnitude measured during this period was 7.3 and it occurred twice, on January 31, 1922, off the north coast and on December 20, 1932, in west-central Nevada.

Historically, the most number of quakes were observed during the month of June, followed by October. From 1836 to 2005, the month of June witnessed almost 20 major shocks, all measuring at a magnitude of 5.5 or higher. August and September are months that have the least amount of shocks with a magnitude high enough to cause impact.

Notable And Major Californian Earthquakes

In the history of California, there have been many notable and major earthquakes. Some of these earthquakes have caused great destruction and loss of life, while others have been relatively minor in comparison.

The first mention of an earthquake in the active fault of San Andreas dates back to the 1600s. However, the first time an earthquake in California was officially reported was on July 28, 1769.

The movement was reported by a Spanish expedition routing the sea. One of the most recent earthquakes in the history of the state happened on July 8, 2021. The shock was in Antelope Valley, Inyo National Forest, located southwest of Smith Valley.

This earthquake occurred as a series of shocks. The largest magnitude measured was around 6, and it was felt pretty wide.

The El Mayor-Cucapah earthquake struck Baja California on April 4, 2010. This region lies to the south of the Mexican border.

This disastrous earthquake had a magnitude of 7.2 and a depth of 6.2 mi (10 km). It sent shocks all across the southern Californian area. The 2019 Ridgecrest earthquake is one of the most notable shocks in the state in recent history.

Reasons For Earthquakes

It is a well-known fact that this US state is famous for its earthquakes. In fact, California is one of the most active seismic zones in the world. But how exactly does this happen? Read on to know.

Earthquakes are natural disasters that occur when two plates of the Earth's crust grind against each other. An earthquake can happen because the Earth's plates are moving, or because of some outside force like volcanic activity and both of these can disrupt the Earth's surface.

Sometimes, the pressure from the movement of these plates builds up until finally there's an explosive release and an earthquake happens.

California is prone to earthquakes because it is located on top of two major tectonic plates. One is the Pacific Plate and the other one is the North American Plate.

This makes California one of the most seismically active regions in the world. In fact, California has thousands of earthquakes every year. While most of these earthquakes are too small to cause damage, there are exceptions, and a major earthquake can cause widespread destruction.

Damage Due To Earthquakes

An earthquake can be quite disastrous if it crosses a certain magnitude. In California, there has been a history of rampant damage due to earthquakes, ranging from surface rupture on roads to loss of property and people.

Hayward struck California on October 21, 1868, rupturing the Hayward Fault which lay between Berkeley and Fremont. This earthquake had a magnitude of 6.8 and was quite disastrous, resulting in many injuries and around 30 deaths.

On March 26, 1872, the 7.8 magnitude Lone Pine ravaged the tiny town of Lone Pine in Inyo County. This quake killed around 10% of the town's population at the time and was felt up to Nevada, Oregon, Arizona, and Utah.

Another earthquake that had disastrous after-effects was the Long Beach earthquake of 1933. This quake had an epicenter off the shore of Long Beach, on the Newport–Inglewood Fault in southern California.

This particular earthquake had a magnitude of 6.4 and caused widespread chaos throughout the southern Californian region. There was extensive damage to buildings and other property, as well as many fatalities.

Most injuries and deaths happened when people attempted to flee and got trapped under the debris. El Mayor-Cucapah was one of the largest earthquakes in southern California since 1892 and resulted in a lot of damage, ranging from shaken homes and buildings to deaths.

Earthquakes can have life-threatening effects. Therefore, the government has action plans in place to help Californian residents survive and recover from a shock of high magnitude. Necessary guidelines about safety and survival are available on public information websites. In addition, drills are carried out for school students to practice how to survive in the incident of a bad shaker.