Why California's BIG EARTHQUAKE Hasn't Hit Yet
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Mar 31, 2025
Why California's BIG EARTHQUAKE Hasn't Hit Yet
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0:00
For as long as I can remember, the big one in California was right around the corner
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And with it, predictions claimed that California would be split in two, Los Angeles would be
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leveled, and there would just be general mayhem and carnage everywhere. But despite all of these predictions, the big one has yet to actually hit
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So where is California's big earthquake, and why is it taking so long to get here
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I don't know about you, but I've been waiting for the really large San Andreas earthquake to hit for a long time now
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There was even a whole movie made back in 2015 that hyped up the potential of a large San Andreas earthquake aptly named San Andreas
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So I got curious recently when yet another large earthquake hit Japan just about a month ago
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And it got me thinking about why Japan has been so unlucky and California has been so, well, lucky
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And so I dug in and, as it turns out, the reason is highly geographic
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Earthquakes are one of the most dynamic and impactful natural events on Earth
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shaped by the movement and interaction of these huge plates underground that we call tectonic plates
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And the geography of earthquakes is tied to these tectonic plates, particularly where they meet each other, though not always
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These boundaries are zones of intense geologic activity where plates diverge, converge, or slide past one another, creating the conditions for earthquakes
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Globally, the most seismically active regions are found along the edges of the Pacific Ocean, a zone known as the Ring of Fire
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This horseshoe-shaped belt stretching from the western coasts of North and South America
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to Japan, Southeast Asia, and then all the way down to New Zealand
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is home to about 90% of the world's earthquakes. And the reason for this is because the Ring of Fire is mostly a series of subduction zones
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where one tectonic plate is forced underneath another. This leads to very powerful seismic events
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Notable earthquakes in this region would include the 2011 Tohoku earthquake in Japan
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which triggered a massive tsunami, and the 1960 Valdevia earthquake in Chile
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the most powerful earthquake ever recorded with a magnitude of 9.5. But there are other significant regions of the world where earthquakes occur
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such as the Himalayan region, the Mediterranean Alpine region, and the Mid-Atlantic Ridge
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The Himalayan region, where the Indian Plate is colliding with the Eurasian Plate
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is known for its potential for large earthquakes, such as the 2015 Gorkha earthquake in Nepal
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The Mediterranean Alpine region, stretching from southern Europe to northern Africa, is another significant area of seismic activity
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In 2019, a 6.4 earthquake rattled Albania, causing over 50 deaths and 3,000 injuries
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And of course, there's the Mid-Atlantic Ridge, a divergent boundary running down the center of the Atlantic Ocean
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which experiences frequent but generally smaller earthquakes as the Eurasian and North American
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plates move apart, though this is specifically why Iceland has so much volcanic activity
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The distribution of earthquakes is not uniform, to say the very least, with certain areas experiencing
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far more frequent and intense seismic activity than others. This uneven distribution is a direct
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result of the Earth's tectonic processes. In some regions, such as Central and Eastern North America
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earthquakes are less common and often less intense, such as the 1811 to 1812 New Madrid
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earthquakes in the central United States. And this brings us to California. Located on the western
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edge of North America is one of the most seismically active regions of the world
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owing to its position along the boundary between the Pacific and North American plates The primary feature responsible for California earthquakes is of course the San Andreas Fault a transformed fault that runs approximately 800 miles through the state
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from the Salton Sea in the south to Cape Mendocino in the north. The fault marks the boundary where
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the Pacific Plate slides past the North American Plate, generating significant seismic activity
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All that said, California's seismic activity is not limited to the San Andreas Fault
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The state is crisscrossed by numerous other faults, including the Hayward Fault in San Francisco Bay, the Garlock Fault in Southern California, and the Elsinore Fault in the Inland Empire
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Each of these faults contributes to the very complex seismicity of the region, with varying levels of activity and potential for large earthquakes
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So speaking of large earthquakes, in recent decades, there has been a growing awareness for the potential for a major earthquake along the southern segment of the San Andreas Fault, often referred to as the big one
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Scientists have warned that such an event could have devastating consequences for Southern California, particularly Los Angeles
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but this earthquake has yet to materialize, which is weird because the United States and California
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are no strangers to large, devastating earthquakes. So I don't know if you've heard
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The United States is very seismically active, more so than you probably think
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Because despite California getting much of the attention when it comes to earth rattlers
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there are many places all around the country that have the potential for large earthquakes
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mostly because the country is situated at the intersection of several tectonic plates
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including the Pacific, North American, and Juan de Fuca plates, which are responsible for most of the seismic activity, but not all of it
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Of course, one of the most significant earthquakes in U.S. history was the 1906 San Francisco earthquake
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Occurring on April 18, 1906 with a magnitude of 7.9, this earthquake was caused by a rupture along the San Andreas Fault, the most infamous fault line in U.S. history
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The quake and the subsequent fires devastated San Francisco, destroying over 80% of the city and killing approximately 3,000 people
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This earthquake was not only a defining moment for California, but also a catalyst for advancements
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in seismology and earthquake engineering in the United States. Another major event is the series of earthquakes that struck the New Madrid seismic zone in
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the winter of 1811 and 1812. This region, located in the central United States along the Mississippi River, experienced
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a series of quakes estimated to be between magnitude 7.0 and 8.0
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The earthquakes were so powerful that they reportedly caused the Mississippi River to
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flow backward temporarily and created Real Foot Lake in Tennessee. Despite being sparsely populated at the time thankfully these quakes were felt as far away as the east coast and remain some of the most powerful earthquakes to occur in the contiguous United States Not to be left out Alaska due to its position on the Pacific Ring of Fire also experiences
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frequent seismic activity. The most notable earthquake in Alaskan history is the 1964 Good Friday earthquake
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With a magnitude of 9.2, it is the most powerful earthquake ever recorded in North America and
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the second most powerful worldwide. The quake caused widespread destruction in Anchorage and other areas and generated a
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massive tsunami that reached as far south as California. The 1964 earthquake highlighted the seismic risks in Alaska
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a state that continues to experience regular tremors. And of course, there's the relatively newly unearthed Cascadia subduction zone earthquake
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in the Pacific Northwest. This area, where the Juan de Fuca Plate is being forced underneath the North American
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plate is capable of producing megathrust earthquakes. The last known megathrust earthquake
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in this region occurred in the year 1700 with an estimated magnitude of 8.7 to 9.2. The event
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caused a tsunami that affected the coastlines of Japan all the way across the Pacific Ocean
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indicating the immense power of these types of quakes. Scientists believe that another similar
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event is possible and as such, the region remains under very close observation. But it's California
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particularly Southern California that has become the most well-known recent hotspot for seismic activity
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The Northridge earthquake of 1994 is one of the most well-known in recent history
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With a magnitude of 6.7, the quake struck the densely populated San Fernando Valley
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causing significant damage and killing 57 people. The Northridge earthquake was notable not just for its immediate impact
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but also for prompting changes in building codes and infrastructure designed to better withstand future quakes
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While these large earthquakes capture the most attention in the United States, smaller earthquakes occur regularly across the country, but especially in the western states
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The U.S. Geological Survey estimates that several thousand earthquakes occur each year in the U.S.
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though most are too small to be felt. These smaller quakes serve as reminders of the continuous movement of the Earth's tectonic plates
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and the potential for larger, more destructive events. But if you're noticing a particular trend here, it's that
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While California is certainly still very seismically active, the Big One has been predicted for so long and has yet to materialize
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So where is it? The concept of California's Big One has loomed large in the public consciousness for decades
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referring to the anticipated massive earthquake expected along the southern segment of the San Andreas Fault
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Scientists have long predicted that a major seismic event is overdue in this region
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yet despite these warnings, the big one has yet to occur. This delay has kind of puzzled experts and raised questions about the underlying factors
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influencing the timing and severity of earthquakes in Southern California. Among these factors, the drying up of the Salton Sea has emerged as a potential influence
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adding complexity to an already intricate seismic landscape. The Salton Sea, California's largest lake, was formed in 1905 when a breach in the Colorado River Irrigation C system allowed water to flood into the Salton Basin
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Over the years, the Salton Sea became an important ecological and recreational area, but it's been shrinking steadily due to a combination of factors, including reduced inflow from agricultural runoff, increased evaporation rates, and water diversions for urban use
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The drying up of the Salton Sea has had significant environmental impacts
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such as increased dust pollution and loss of habitat for migratory birds
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But it may also be playing a role in the region's seismic activity
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One of the reasons why the big one hasn't struck yet could be linked to the changing conditions around the Salton Sea As the lake dries up the weight of the water that once occupied the basin is significantly reduced This reduction in pressure could potentially alter
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the stress distribution along nearby fault lines, including the southern section of the San Andreas
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Fault. Some scientists theorize that the decreased pressure could either delay or trigger seismic
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activity, depending on the complex interactions between the fault system and the changing weight
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of the Earth's crust in the region. Additionally, the shrinking Salton Sea
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has exposed new areas of the Earth's crust, which could also influence local seismicity
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The region around the Salton Sea is geologically active with numerous faults in geothermal activity
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As the water recedes, the Earth's crust might be adjusting to the changing conditions
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potentially releasing stress in ways that could either delay or precipitate earthquakes
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This process, known as post-glacial rebound in other contexts, could be similar in principle, where the Earth's crust slowly responds to the removal of large
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amounts of water. Beyond the Salton Sea, though, the timing of the Big One is influenced by the
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natural variability of earthquake cycles along the San Andreas Fault. Earthquakes don't occur
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at precise intervals, but rather as a result of accumulated stress along fault lines reaching a
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critical threshold. While the southern San Andreas Fault is considered overdue for a major earthquake
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based on historic patterns, the exact timing remains uncertain. This unpredictability is due in part due to the complex interactions
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between multiple faults in Southern California, including the San Jacinto, Elsinore, and Imperial Faults
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which can transfer stress and influence each other in ways that are difficult to predict
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In 2019, a series of powerful earthquakes known as the Ridgecrest Earthquakes
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struck in the Eastern California Shear Zone, and this may have had an impact
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on when the big one eventually unleashes. Moreover, recent research has suggested
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that smaller seismic events, known as slow earthquakes or aseismic creep, may be occurring along portions of the San Andreas Fault
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These slower movements release stress gradually over time without producing a large, destructive earthquake
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If this process is happening to a significant extent, it could also help explain why the big one has not yet occurred
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as the fault may be slowly relieving some of the stress that would otherwise build up and result in a major quake
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Finally, in addition to these geologic factors, human activities may also be playing a role here
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The extraction of groundwater, oil, and gas in Southern California can cause subsidence and potentially influence seismic activity
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by altering stress conditions. And while the direct link between these activities
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and the delay of the big one is not yet fully understood, they do represent additional variables in an already very complex system
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The drying up of the Salton Sea, therefore, is just one piece of a larger puzzle
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that includes natural seismic cycles, geologic processes, and potentially human influences. So while it may be easy to write off scientists' predictions of the big one
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hitting California in the near future simply because it hasn't materialized yet
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The reality is that there are so many incredible variables at play that impact a fault like the San Andreas because it's a land-based fault line
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And that means that we humans have an outsized impact on it as compared to something like the Cascadia subduction zone, which lies underneath the ocean
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California is still very seismically active, even if the big one hasn't hit
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The Ridgecrest earthquakes in 2019 are a fairly recent example of that
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But that doesn't mean it won't hit at some point. It just means that our ability to predict earthquakes is far less precise than maybe we previously thought
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I swear, knowing my luck, as this video comes out, the big earthquake is just about to hit California
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But I really hope you enjoyed it. And if you did, please like the video and subscribe to my channel
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And of course, I'll see you guys next week
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