Why do earthquakes happen? And should we worry about the “Big One”?

Hello Science Fans!

Earthquakes are terrifying. And with recent events, people are more worried than ever. How can they not be? Just last Feb. 6, 2023, 20,000 people died in Turkey and Syria due to a magnitude 7.8 earthquake. And this was less than a year after the June 22, 2022 magnitude 6.1 earthquake in Afghanistan that killed more than 1,100 people. There was also Haiti in Aug. 14, 2021 where a magnitude 7.2 earthquake killed more than 2,200 people. And that’s just in the past 3 years.

And when people start talking about earthquakes, they also keep mentioning “the big one”.

The term “the big one” is often used to refer to a possible future earthquake of a very large magnitude. And when a region experiences a series of smaller earthquakes, it is often seen as a warning sign that a larger earthquake could occur in the future. The potential impact of “the big one” and the lack of trust in the level of preparedness and response capabilities of the affected region, are what makes it scary. Imagine, in areas with high population densities, such as cities, “the big one” could destroy buildings, and transportation systems, which could lead to loss of life. This is why earthquake preparedness is crucial in areas where the risk of earthquakes is high.

But why do earthquakes happen? And what can we do to prepare for it?

But before we answer that question using science, I want to greet our new viewers. My name is Chona and I’m your resident Filipina scientist.

I’m a researcher who has studied environments in mountains and in oceans.

I’m a teacher in the field of Biology and Environmental Science, and I am often curious about how changes in the environment will affect our quality of life.

And SHE-ensya is my science communication channel where I talk about the science behind many things — including the ones that scare us.

So, let’s talk about earthquakes.

Earthquakes are natural phenomena that occur when energy is released from within the Earth’s crust, causing shaking or vibrations of the ground. These vibrations can vary in intensity and can cause damage to any structure on the surface of the planet.

The primary cause of earthquakes is the movement of tectonic plates, which are massive slabs of rock that make up the Earth’s surface. Tectonic plates move due to the heat generated from the Earth’s core and the mantle, causing them to shift and collide with each other. When two plates collide, one may slide under the other, creating a subduction zone. A subduction zone is an area where two tectonic plates meet, with one plate sliding beneath the other and sinking into the mantle. This process can lead to the formation of volcanic arcs, and the creation of deep ocean trenches.The movement of the plates at these zones can cause large amounts of stress to build up, which can then be released in the form of an earthquake.

Earthquakes can also be caused by volcanic activity. One way is through the movement of magma beneath the Earth’s surface, which can cause the surrounding rock to crack and shift, leading to earthquakes. Another way is when the pressure from the rising magma causes the overlying rock to fracture and generate seismic waves. Additionally, the movement of magma within a volcano can cause the ground to bulge and shift, which can also lead to earthquakes. These earthquakes can be a warning sign of an impending volcanic eruption and can provide valuable information for monitoring and predicting volcanic activity.

But not all earthquakes are natural, some can be caused by human activity! Human activities can cause earthquakes through a process known as induced seismicity. This occurs when human activities, such as mining, drilling, and the construction of large reservoirs, create changes in the subsurface pressure or stress fields that can lead to earthquakes. For example, the injection of fluids into deep underground wells, such as those used in oil and gas extraction or wastewater disposal, can cause the pressure in the subsurface to increase, leading to the formation of new faults or the activation of pre-existing ones. Similarly, underground mining can cause stress changes that can trigger earthquakes.Human-induced earthquakes can vary in size and intensity, from small tremors that are barely perceptible to larger earthquakes that can cause damage to buildings and infrastructure. 

Earthquakes can also be differentiated based on their origin below the Earth’s surface.

We can have shallow earthquakes that occur at a depth of less than 70 kilometers below the Earth’s surface. They are usually associated with the movement of tectonic plates at or near the Earth’s surface, and these are scary because they are known to cause significant damage to buildings and infrastructure.

The are also intermediate earthquakes that occur at a depth between 70 and 300 kilometers below the Earth’s surface. They are typically associated with the subduction of oceanic plates beneath continental plates, and can cause moderate to strong shaking.

And then there are deep earthquakes with origins at a depth greater than 300 kilometers below the Earth’s surface. They are usually associated with the movement of tectonic plates in subduction zones, and can cause less intense shaking due to the depth at which they occur. However, they can still cause damage and be felt over a wide area.

When earthquakes happen, they are often described using their magnitude and intensity. But how do we measure these characteristics?

Earthquakes are measured using instruments called seismometers, which record the vibrations or seismic waves produced by the earthquake. The data recorded by seismometers is used to determine the earthquake’s magnitude, which is a measure of the energy released during the earthquake.

There are several scales used to measure the magnitude of an earthquake, including:

1. Richter scale: This scale is based on the amplitude of the largest seismic wave recorded by a seismometer and is the most well-known scale for measuring earthquake magnitude.
2. Moment magnitude scale: This scale takes into account the amount of energy released by the earthquake and is considered a more accurate measure of earthquake magnitude for larger earthquakes.
3. Modified Mercalli Intensity scale: This scale measures the intensity of shaking and damage caused by an earthquake at a specific location and is used to determine the earthquake’s effects on the surrounding area.

Seismologists also use the data recorded by seismometers to locate the epicenter of the earthquake, which is the point on the Earth’s surface directly above the location where the earthquake originated.

Measuring earthquakes is important for monitoring seismic activity and understanding the risks and potential impacts of earthquakes. It also allows for the development of earthquake early warning systems, which can provide valuable time for individuals and communities to prepare for and mitigate the effects of an earthquake.

Earthquakes are natural characteristics of our planet. They cannot be avoided. But this doesn’t mean that our situation is hopeless. There are ways for us to prepare for an earthquake and lessen its negative impacts.

In order to lessen the casualties of earthquakes, governments Develop and enforce building codes: Building codes that incorporate earthquake-resistant design features can help ensure that buildings and infrastructure can withstand seismic activity. And older buildings that do not meet modern seismic standards can be retrofitted with structural upgrades to improve their earthquake resistance. Governments should develop emergency response plans that include procedures for evacuating and providing medical assistance to those affected by earthquakes, and to make sure to communicate this regularly to the communities they serve.

Early warning systems that provide advance notice of impending seismic activity can help individuals and communities prepare and take appropriate action. But can we predict when an earthquake is coming?

While scientists have made significant progress in understanding the mechanisms that cause earthquakes, they have not yet developed a reliable method for predicting them with precision. One of the main challenges in predicting earthquakes is that they occur deep within the Earth’s crust and are caused by complex and dynamic geological processes. The stresses and strains that build up in the Earth’s crust over time are influenced by a wide range of factors, including tectonic plate movements, the composition of the underlying rock, and the presence of fluids such as water and magma. These factors can change rapidly and unpredictably, making it difficult to predict when and where an earthquake will occur. Another challenge is that earthquakes can occur on a wide range of time scales, from seconds to centuries, and can vary greatly in terms of their size and impact. While scientists have identified certain regions and fault lines that are more prone to seismic activity, it is not yet possible to accurately predict the timing, location, or magnitude of an individual earthquake.

And I think that’s the scariest thing about earthquakes — we cannot predict when they’ll happen. At least not yet.

Of course, this doesn’t mean we’re powerless in the face of this potentially gigantic catastrophe. And we don’t even have to depend on our government to protect us. There are several things we can do to help with our survival when it comes to earthquakes:

1. Develop an emergency plan: Create a plan with your family or household that includes procedures for evacuating your home or building, a designated meeting place, and emergency contact information.
2. Prepare an emergency kit: Assemble a kit with essential items such as water, non-perishable food, first-aid supplies, and a flashlight.
3. Secure your home or building: Secure heavy furniture and appliances, install latches on cabinets and drawers, and fasten objects on walls or shelves to prevent them from falling during an earthquake.
4. Stay informed: Monitor news and weather reports for information about earthquakes and be aware of the potential risks in your area.
5. Practice earthquake drills: Conduct regular earthquake drills with your family or workplace to practice emergency procedures and ensure that everyone knows what to do in the event of an earthquake.
6. Participate in community preparedness efforts: Work with your local government and community organizations to develop and implement earthquake preparedness plans and initiatives.
7. Maintain earthquake insurance: Consider obtaining earthquake insurance to help cover the costs of damages that may occur during an earthquake.

While it is not possible to prevent earthquakes from occurring, taking these steps can help reduce the potential impacts and risks associated with earthquakes.

And while earthquakes are scary and dangerous, they play a huge role in shaping the Earth’s surface and influencing geological processes. The movements that lead to earthquakes create new landforms, such as mountains and ocean basins, and drive the formation of new geological features over time. Some types of earthquakes can also generate valuable mineral deposits, such as gold and copper. Understanding the geological processes that lead to these deposits can help inform mining practices and contribute to the development of new mineral resources.

Share our earthquake video below to friends and family to share life-saving information about it:

Thank you so much for dropping by!

If you have any comments, questions or suggestions, please don’t hesitate to contact me, your resident Filipina scientist, in the comments section below.

And remember, when in doubt, always use your (con)science!