Are Earthquakes More Frequent Now? What Does Science Say?

Are Earthquakes More Frequent Now? What Does Science Say?

The prospect of an earthquake is frightening to many of us, and the feeling we have is that there have been a lot of earthquakes in recent years. But are earthquakes actually increasing in frequency? Or are we simply more aware of what is happening in the world now, thanks to improved technology and increased communication and reporting? And if earthquakes are becoming more frequent, is climate change a contributing factor to these natural disasters?

Click through the gallery below to see these answers and more.

© Shutterstock

Seismic activity

Temporary increases and decreases in seismic activity are a natural part of the fluctuating earthquake rate. But are there more earthquakes now than in the past?

©

Stock struggle

Seismic activity

Well, there are certainly many more seismic instruments available to measure seismic activity, which means we are able to record more earthquakes.

©

Stock struggle

Equipment improvement

The vast improvement in the quality and quantity of equipment that records seismic activity means that smaller earthquakes can now be detected, in remote locations (including the sea floor).

©

Stock struggle

But how many are there?

About 20,000 earthquakes occur around the world each year, or about 55 earthquakes per day.

©

Stock struggle

Increased risk

The risk of earthquakes is increasing as a result of increased human and economic exposure because structures are built in areas of high seismic risk.

©

Stock struggle

potential impact

For example, although Alaska is the most seismically active state in the United States, the risk and impact of an earthquake is greater in California because the potential losses are greater.

©

Stock struggle

Earth’s crust

The Earth’s crust is like an eggshell. It is thin compared to the planet and looks like an egg when cracked. The crust is made up of large pieces called plates that move.

©

Stock struggle

painting movement

The North American plate is moving west-southwest at a rate of 2.5 cm per year, while the Pacific plate is moving northwest at a rate of 7.5 to 10 cm per year.

©

Stock struggle

painting movement

The movement of plates around the world is the main source of stress that leads to earthquakes. Those with a magnitude of seven or greater tend to occur about 15 times a year.

©

Stock struggle

How does that happen?

Large earthquakes are often followed by foreshocks, aftershocks, and smaller earthquakes, which can be very large.

©

Stock struggle

Seismic groups

Many earthquakes occur as a series of smaller earthquakes clustered together, with no identifiable main shock. These are sometimes called earthquake swarms.

©

Stock struggle

Seismic groups

At the University of Utah, a group of researchers has been studying the earthquakes that occur there. They are essentially small, imperceptible outbreaks, clustered in time and space.

©

Stock struggle

Seismic groups

These are called “seismic clusters” and they strike an area over a short period of time. In central Utah, dozens of them occur within a few hours before the break. This happens over and over again.

©

Stock struggle

Where do earthquakes occur?

Earthquakes often occur along plate boundaries, when sudden movements of “trapped” plates release elastic stress energy, sending out seismic waves that cause the ground to shake.

©

Stock struggle

Where do earthquakes occur?

In rare cases, earthquakes occur within plates (intraplates) in areas of weakness, such as reactivation of old faults or cracks.

©

Stock struggle

Atmospheric pressure

According to NASA, when large changes in atmospheric pressure occur in conjunction with hurricanes, it causes the release of energy stored in the Earth’s crust.

©

Stock struggle

Seismologists

Seismologists have focused on trying to predict the location, timing and magnitude of earthquakes in recent years. However, the planet’s powerful movements remain a mystery.

©

Stock struggle

Climate change

However, it cannot be ignored that the effects of climate change are becoming more evident, with unusual weather conditions becoming the norm rather than the exception.

©

Stock struggle

The power of glaciers?

New research published in 2023 explored the possibility that earthquakes could be caused by the activity of Earth’s glacial cycles.

©

Stock struggle

Korean fault zones

In the study conducted in South Korea, researchers looked at the possible relationship with interglacial periods that occur in cycles of every 100,000 years.

©

Stock struggle

interglacial periods

By analyzing more than 450 electron spin resonance (ESR) ages from earthquakes in fault zones on the Korean Peninsula, they found that the formation coincided with five important interglacial periods.

©

Stock struggle

interglacial periods

Scientists have hypothesized that large changes in sea level during these periods played an important role in triggering seismic events.

©

Stock struggle

Ice discharge

One theory is that this may result from the release of pressure from glacial degassing as the weight of ice on the Earth’s mass decreases with melting.

©

Stock struggle

glacial melt water

However, melting ice sheets may be far enough away from the Korean Peninsula to cause this response. Instead, the researchers believe it suggests that compressional stress in the underlying lithosphere caused by the loading of water from melting glaciers (which causes sea level rise in the Pacific Ocean) may be the solution.

©

Stock struggle

Ramifications

The research has implications for seismic activity, as climate change affects the melting of glaciers. And as sea levels rise, if true, it means that stress on the lithosphere could trigger new earthquakes.

©

Stock struggle

monsoon season

Separately, scientists have also discovered that the monsoon season increases the weight of water in the Indian subcontinent’s crust to such an extent that it changes seismic activity in the Himalayas.

©

Stock struggle

Ice earthquakes

As glaciers melt, they also displace magma underground, causing changes beneath the Earth’s crust.

©

Stock struggle

Ice earthquakes

This leads to increased volcanic activity, which is directly linked to the development of earthquakes, known as ice quakes.

©

Stock struggle

climate change impact

If earthquakes become more frequent due to rising sea levels linked to climate change, it’s a good idea to be prepared, just in case.

©

Stock struggle

to prepare

The actual shaking from an earthquake usually isn’t what causes injuries. However, walls, ceilings, and collapsing glass from buildings tend to fly off or fall. Indoors, seek shelter under a sturdy desk or table until the shaking stops. Outdoors, avoid trees, buildings, power lines, and lampposts, and fall until the shaking stops.

Sources: (USA Today) (BGS Earthquake Seismology) (Phys.org) (USGS) (World Economic Forum) (Atmos) (Worldcrunch)

Read also: The violent earthquake that moved the Earth’s axis and shortened the length of days

©

Stock struggle