Why Recent Unusual Activities in the San Andreas Fault Could Trigger a Major Earthquake

The ground under us always moves a little. But in California, at the San Andreas Fault, this movement is a big deal. This huge crack in the Earth, about 750 miles long, is where two big plates of the Earth rub against each other. Scientists have been watching it closely for years because they know a big earthquake will happen there someday. Lately, some strange things have been happening along different parts of the San Andreas. This is making scientists worry that a really big earthquake, the one people have feared for a long time, might be coming. We need to understand these new things and what they might mean so we can be ready, especially because there’s always a chance of an earthquake today.

The San Andreas Fault is like many pieces connected together. Some parts move a little bit all the time, causing small shakes. But other parts get stuck and build up a lot of pressure over many years. When this pressure gets too high, it can cause big and strong earthquakes. We know from the past that big earthquakes have happened on the San Andreas every few hundred years. The last big one in the southern part was in 1857. Many scientists think that this part is now overdue for another big one, maybe around magnitude 7.9. So, when they see strange things happening now, they get even more worried that a big earthquake today or soon could be more likely.

VIDEO: Why Recent Unusual Activities in the San Andreas Fault Could Trigger a Major Earthquake

‘Part 1: Lots of Small Shakes and Changes in Slow Movement
One of the strange things happening at the San Andreas Fault is that there have been many small earthquakes in areas that don’t usually have so many. These are called swarms, where you get lots of little to medium shakes in one place over a short time, without one really big one. Usually, these swarms happen in places with volcanoes or where water moves underground. But recently, they’ve been happening in some of the stuck parts of the San Andreas, and this is making scientists pay attention. For example, there have been more tiny shakes in some parts of Southern California that haven’t had much shaking for a long time. These little shakes by themselves don’t cause much damage, but the fact that there are more of them in unusual places might mean that the pressure along the fault is changing. This could mean that the fault is starting to become unstable in some areas, which might lead to a bigger break. Scientists are watching closely to see if an earthquake today is more likely because of these changes.

Another thing they’ve noticed is that the slow movement in some parts of the San Andreas Fault is changing. In Central California, there’s a part that moves slowly and steadily all the time. This slow movement releases some of the pressure and makes a big earthquake there less likely. But lately, this slow movement has been speeding up or slowing down in some places. These changes could put more pressure on the parts of the fault that are stuck. For example, if the middle part moves faster, it could push harder on the stuck southern part, making it closer to breaking. If the slow movement stops, that could also change how the pressure builds up. So, watching these small changes in how the fault moves is very important for understanding the overall pressure and whether a big earthquake today or soon is more likely.

Part 2: Strange Changes in Water Pressure Underground
New research is also showing that changes in the pressure of water underground might affect when earthquakes happen at the San Andreas Fault. If there’s more water in the fault zone, it can make the fault slip more easily, like putting oil on something to make it slide. Scientists have been measuring the water levels deep underground along the fault, and they’ve seen some strange changes that don’t seem to be from rain or normal water changes. These strange water pressure changes might be connected to things happening deeper in the Earth or changes in how easily water can flow through the fault.

For example, some studies say that when there are slow-slip events (where the fault moves very slowly and silently deep underground), it might change the water pressure in the stuck parts above. Even small changes in this pressure could be enough to trigger a bigger earthquake sooner. So, the fact that scientists are seeing these unusual water pressure changes in areas that are likely to have earthquakes is worrying and needs more study. Understanding how water pressure and the fault work together is key to getting better at predicting if an earthquake today or in the future is more likely. These findings show that there are many connected things that can cause earthquakes in big fault systems.

Part 3: More Gas Coming Out of the Ground
Another interesting thing that scientists are looking at is the amount of certain gases coming out of the ground along the San Andreas Fault. Some studies suggest that when the ground is under more stress before an earthquake, it can release gases like radon or helium from the fault zone. We don’t fully understand this yet, and not all scientists agree that this can predict earthquakes. But recently, there have been reports of more of these gases coming out of the ground in some parts of the San Andreas, and some scientists are paying attention to this. If these increases in gas happen regularly before earthquakes, it could be another way to watch what the fault is doing and if an earthquake might be coming.

For example, some places along the San Andreas have machines that constantly measure the amount of certain gases in the air. These machines have reportedly shown sudden increases in some gases that don’t seem normal. While these increases could be for other reasons, the fact that they are happening in areas that have earthquakes makes scientists want to look closer. They are trying to figure out why these gases might be released and if they can be a reliable sign that a big earthquake today or soon is more likely. This is a new area of research, but any clue that could help us know when an earthquake might happen is very important.

Part 4: History Shows Big Earthquakes Are Due
Besides the strange things happening now, the history of big earthquakes on the San Andreas Fault also makes scientists worried. Like we talked about before, the southern part of the fault hasn’t had a big earthquake since 1857. Based on how often big earthquakes have happened there in the past, many scientists think it’s time for another one, maybe a magnitude 7.5 or even bigger. The fact that a big earthquake today is more likely in this area than in other parts of the fault makes any unusual activity there even more concerning. This southern part of the fault goes through very populated areas of Southern California, so a big earthquake there could be very bad. It could cause a lot of damage to buildings, roads, and important systems like water and gas lines. It could cost hundreds of billions of dollars and really disrupt the lives of millions of people for a long time. That’s why it’s so important to be prepared. We need to know the risks and do things like secure our homes, have emergency kits ready, and make plans with our families. The recent strange things happening at the fault are a good reminder that the threat of a big earthquake is always there, and we need to be ready for an earthquake today or any day.

All these strange things happening at the San Andreas Fault — more small shakes, changes in slow movement, strange water pressure, more gas coming out of the ground, and the fact that a big earthquake is due in the south — are all connected and worrying. We can’t say for sure when a big earthquake will happen, but these signs suggest that the pressure and behavior of the fault might be changing in important ways. Scientists need to keep watching closely and studying these things to better understand what’s going on and to get better at predicting if a big earthquake today or soon is more likely. The best thing we can do now is to be prepared before the ground starts shaking.