We are all familiar with California’s natural beauty, from beaches and forests to large cities and mountains. But, gazing over this beautiful landscape may have you wondering, does California have any volcanoes?
California contains 20 known volcanoes. While many of these are currently thought to be inactive, the United States Geological Survey (USGS) has identified seven volcanoes that exhibit potential signs of risk. These volcanoes are spread throughout the state, from the Oregon border down to San Diego.
But are these volcanoes at risk of erupting? When was the last time a volcano erupted in California? As you read, you’ll learn everything you wanted to know about volcanoes in California and some things you hadn’t even thought about!
Will You Find Volcanoes in California?
California is such a large state that natural disasters are an unfortunate guarantee. Known as the state with the most damage-causing earthquakes, California also experiences brutal wildfires on an annual basis.
Less written about in the news are the volcanoes in California. The fact is, there are currently over 20 volcanoes known in California, seven of which are thought to be active.
Spread throughout the entire state, the list of active volcanoes includes:
- Medicine Lake Volcano
- Mount Shasta
- Lassen Volcanic Center
- Clear Lake Volcanic Field
- Long Valley Volcanic Region
- Coso Volcanic Field
- Salton Buttes
The USGS tracks and monitors these volcanoes regularly. Their research on past eruptions indicates that the seven listed above have a good chance of erupting again. However, whether or not the eruptions will be significant and destructive or small is unknown until the eruption occurs.
These volcanoes are not centralized within the state. Medicine Lake volcano is the furthest north, nestled in the Cascades less than 100 miles from the Oregon border. Salton Buttes, on the other hand, is almost directly due east of San Diego. The rest are spread relatively evenly throughout the state.
Although the idea of volcanoes located near population centers in California seems scary, the rarity of such explosions should be noted. In California, the last eruption of a volcano occurred over 100 years ago, and due to proper warnings being given, nobody was hurt or killed.
When Was the Last Time a Volcano Erupted in California?
Although California has a large number of volcanoes, both active and dormant, eruptions do not frequently occur at all. In fact, the last volcano that erupted in California was Mount Lassen in 1914.
Mount Lassen, located in the Cascades, is only 55 miles away from the city of Redding. It is located in what is known as the Lassen Volcanic Center, which contains multiple smaller volcanoes in addition to Lassen Peak.
The volcanic eruptions at Mount Lassen actually lasted from 1914 until 1921. Roughly 400 eruptions were observed during this seven-year period and were the last volcanic eruptions in the United States until 1980.
The largest eruption at Mount Lassen occurred on May 22, 1915. This explosion was devastating, destroying many natural areas and raining volcanic ash as far as 200 miles to the east.
Future eruptions are not expected to occur for a while in Mount Lassen. The best way to predict future volcanic eruptions is by measuring those of the past, and significant eruptions in Mount Lassen are usually spread out by thousands of years. This isn’t to say it’s not possible – but the likelihood is very low.
Bay Area Answers Fun Fact: The Clear Lake Volcanic Field powers the world’s largest geothermal field, known as The Geysers. These fields can generate enough energy to power the city of San Francisco twice.
Is There a Supervolcano in California?
The term “supervolcano” sounds like you just took a typical volcano and amplified it. In reality, this is relatively close to the truth. A supervolcano is typically large volcanoes that have previously had an explosion that measured as an 8 on the Volcanic Explosivity Index (VEI).
The VEI was created in 1982 and is an open-ended index, having no theoretical max. So far, the largest measured explosions have registered an 8, which are categorized as supervolcanoes.
The United States has one of the largest numbers of supervolcanoes on the planet. This number includes one in California, known as the Long Valley Caldera. Located in Central California, right near the border of Nevada, the Long Valley Caldera is the largest in the United States.
Scientists recently discovered 240 cubic miles of semi-molten magma located under this caldera. Although this is a large amount of magma, the same studies showed that only 27% of it is hot enough to be liquid.
This supervolcano contains enough magma to create an explosion similar to the other famous supervolcano in the United States – Yellowstone National Park.
For comparison’s sake, if the Long Valley Caldera were to explode, it would release over 800 times the amount of debris than the 1980 eruption of Mt. St. Helens. This explosion would be catastrophic to the surrounding area and cause a significant loss of life.
Fortunately, it is very unlikely for an eruption to occur. Scientists have been monitoring this site for decades, and there have been no significant changes in the readings.
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Are There Any Volcanoes Near San Francisco?
Earlier in the post, we listed seven active volcanoes in the state of California. While these volcanoes are spread across the state from north to south and east to west – you may be wondering if there are any located near San Francisco. Well, depending on your definition of “near,” the answer is yes!
Clear Lake Volcanic Field, one of the seven areas of active volcanoes in California, is located only 120 miles from San Francisco. Clear Lake is almost due north of San Francisco and northwest of Sacramento.
Clear Lake is a popular area for tourism and includes the largest natural lake in California. It has a surface area of over 68 miles and is the oldest lake in North America.
As far as volcanic activity, the area is not super active, though many volcanoes are located in the area.
Is There a Volcano Under Los Angeles
If you are within the greater Los Angeles area, you may be wondering if there are any volcanoes under your feet. The answer is no!
While there isn’t a volcano directly under Los Angeles, there is a nearby volcano that could affect the city in the event of an eruption. This volcano is the Coso Volcanic Field.
The Coso Volcanic Field lies 181 miles north of Los Angeles, near Ridgecrest. While there haven’t been any notable eruptions in Coso, it is one of the seven active volcanoes currently being monitored by the USGS.
Coso is a large producer of power. Similar to Clear Lake, Coso produces geothermal energy. The geothermal power generated by Coso is enough to power over 270,000 homes.
Are There Any Extinct Volcanoes in California?
California doesn’t just have active volcanoes. There are many that used to be active that are now considered to be dormant. These volcanoes no longer pose a threat to humanity and are often great places for outdoor activities like hiking.
The most popular dormant volcanoes in California include:
The Sutter Buttes is a small mountain range in the Sacramento Valley located right outside of Yuba City. It is often called the world’s smallest mountain range as it rises from the relatively flat territory of Yuba City and is only 10 miles wide.
The Sutter Buttes were created by volcanic activity, and the highest peak in the group is 2,132 feet above sea level. Most of the range is located on private property, but hiking tours are available at certain times of the year.
The Sutter Buttes’ claim to fame is that they are the only mountain range you can go around in a day.
Cima Lava Field
The Cima Lava Field is another volcanic area that is considered to be inactive. It is located in the San Fernando Valley, near the border of Nevada. It covers roughly 230 square miles, the majority of which are within the Mojave National Preserve.
Here you will see the volcanic remains of small volcanoes known as cinder cones. They pop out of the desert landscape in a conical shape comprised of volcanic rock and provide well-preserved specimens that allow visitors to view the results of volcanic activities in the area.
Explore the Beautiful Volcanic Areas of California
After all the reading about different volcanoes and eruptions, it may seem crazy to want to explore these areas, right? Well, the truth is that these areas are not just known for their volcanoes – but their beauty!
All the areas in the list at the beginning of the post are popular spots for visiting, hiking, and exploring. Scientists regularly monitor each site, and there isn’t expected to be any activity anytime soon.
Lassen Peak is actually within a national park. Lassen Volcanic National Park has nearly half a million visitors annually and is an excellent place for hiking and even has a beautiful lake known as Lake Helen. So if you get the opportunity, it’s highly recommended to explore these beautiful areas.