Massive Crater Three Times the Size of the Grand Canyon Discovered in the United States

By: Julia Mehalko | Last updated: Jul 09, 2024

There are various craters that have been discovered around the United States, thanks to giant asteroids and meteors from outer space crashing into Earth millions of years ago.

These craters can come in all shapes and sizes. Often, average Americans don’t even realize some of these enormous craters even exist — and can be found in their local areas. In fact, the largest crater ever discovered in the U.S. is about three times larger than the Grand Canyon.

What Are Impact Craters?

Impact craters occur on the Earth’s surface after large space rocks, such as meteors or asteroids, hit the planet forcefully, leaving behind a changed landscape.

A side view of crater walls seen in the daytime.

Source: DiscoA340/Wikimedia Commons

These so-called impact events occur over millions of years. As there can be different types of sizes of these space rocks, the types of craters they leave behind can vary.


Discovering Craters

While you may think that it’s easy to spot a crater — after all, they can often appear to be giant holes in the ground — scientists have long explained that discovering craters can be quite difficult.

An aerial view of the Barringer Crater seen in the daytime.

Source: Public Domain/Wikimedia Commons

Scientists conduct many tests to fully understand if an impression on the Earth is from a meteor or asteroid — or if it’s from something else.

Testing Impact Crater Sites

For example, craters can be left behind on the surface of the Earth thanks to volcanic activities or similar explosions. Therefore, not all craters on the planet have occurred because of space rock.

A volcanic crater seen in Iceland in the daytime.

Source: Dave Herring/Unsplash

To accurately decide what formed these craters, scientists conduct testing at impact crater sites to see if they can find rock samples to study. They also look at circular depression images to further uncover information about these sites.

Uncovering Hidden Impact Craters

There are many crater sites around the world that likely haven’t been discovered yet, as weathering and erosion can keep these sites from view.

An aerial view of a massive crater seen in Arizona.

Source: NASA Earth Observatory/Wikimedia Commons

In some cases, scientists have even stumbled upon impact craters without even realizing it, only learning the truth after some studies have been conducted on the region.

Understanding the Planet’s Age

There are a variety of reasons why studying impact crater sites is so important. Scientists explain that these craters can help us better understand how old a planet is.

A close-up of many craters seen on the surface of the moon.

Source: NASA/Wikimedia Commons

For example, Earth is a relatively newer planet than the Moon and Mercury, which have many noticeable craters. The Moon even has about 9,137 craters on its surface that scientists have recognized. More could be found in the future.


Craters in the U.S.

Meanwhile, in the United States, at least 28 different impact crater sites have been found and uncovered by scientists.

An aerial view of a large crater seen in Hawaii on the coast.

Source: Chase O/Unsplash

These crater sites vary greatly in size and range. Diameters can be as small as 0.1 kilometers to as large as 90 kilometers.


The Largest Crater Sites in the U.S.

The largest crater site in the country can be found in none other than the Chesapeake Bay. The Chesapeake Bay Crater was first discovered in the 1990s by C. Wylie Poag, quite by accident.

A view of the Chesapeake Bay water seen on the coast in the daytime.

Source: Steve Adams/Unsplash

Poag was in the region for an offshore drilling project when this stunning discovery was made. The crater site was hidden beneath the Chesapeake Bay’s floor for centuries before Poag finally realized the truth of the Bay.


Larger Than the Grand Canyon

Scientists have deemed the Chesapeake Bay Crater to be the most significant impact crater throughout the entire United States, as it’s enormous.

An aerial view of the Grand Canyon in the daytime.

Source: Tim Hart/Unsplash

This crater site has a diameter of 53 miles. This makes it larger than the Grand Canyon, which has a widest point of about 18 miles.


How This Crater Site Formed

According to scientists, this crater likely formed about 35 million years ago when a bolide — a very large crater-forming body — crashed into what is now known as Virginia’s Hampton Beach.

An aerial view of the two Chesapeake Bay bridges.

Source: Max Shein/Unsplash

This 3 km long bolide traveled at 144,000 miles per hour before colliding with the planet, leaving a 1.3 km deep impact crater behind.


A Changed Region

This collision left behind a completely different region, as scientists believe that the crater impact excavated coastal aquifers.

Sunset seen along the Chesapeake Bay with a pier.

Source: Sara Cottle/Unsplash

In our present day, a large reservoir filled with water 1.5 times saltier than seawater lies in the impact spot. Because this water is incredibly salty, it cannot be used for many purposes, such as for drinking water.


Changing the Rivers

This crater also changed how the rivers flow in the area. For example, rivers like the Rappahannock flow to the Atlantic in a southeast direction.

An aerial view of the South River looking towards the Chesapeake Bay.

Source: Carol M. Highsmith/Wikimedia Commons

Researchers believe that, after this collision, the York and James rivers changed their flow to head northeast to the crater.


How Else Do Craters Impact the Environment?

Scientists have attempted to study the effect that meteor impact sites have on global warming and found that rocks melting at impact sites release carbon dioxide into the atmosphere.

a cloud in the sky that spells out CO2.

Source: Matthias Heydge/Unsplash

Impacts on the Earth also increase the chance of acid rain which forms from a combination of sulfur dioxide and carbon dioxide.


Organism Extinction

Famously, scientists have thought that large meteor impacts have led to the extinction of many species on Earth as the environments are forced to change.

Dinosaur models seen in red light.

Source: engin akyurt/Unsplash

A deep meteor impact 65 million years ago is thought to have been behind a mass extinction event that included many dinosaurs, birds, insects, mammals, and plants.


Chaotic Early Universe

Meteor impacts were much more common in the early history of the universe. Around 4 billion years ago, the Earth was constantly pummeled by impacts of much greater frequency and size.

The Earth's surface.

Source: Bhavya Pratap Singh/Unsplash

It is thought that the Earth’s moon is one of the oldest pieces of evidence for this bombardment, and the moon itself is thought to have originally been a piece of the Earth that has broken off.


Studying Craters

By observing and counting impact craters, researchers can learn a lot about what conditions were like in the past. An older planetary surface tends to have more clusters of craters, which is a testament to its age because it has had more time to accumulate them.

A crescent moon in the black sky.

Source: Kym MacKinnon/Unsplash

Using craters, scientists can guess the age of planets and planet-like entities in space without having to land a spacecraft and study them directly.


Importance of Study

In addition to learning about the past, studying impact craters can help scientists predict future collisions that might have a devastating impact on our planet and the solar system.

A view of the asteroid Dinkinesh and its satellite in black space.

Source: NASA/Wikimedia Commons

At least once per year, a 4-meter asteroid will have a near-miss with the Earth, though larger meteorite strikes happen at a much slower rate.


Close Approaches

In 2022 there were 126 incidents of what astronomers would call a “close approach” where a meteor got closer to Earth than the moon is.

A lit-up moon in a dark black sky.

Source: Esaias Tan/Unsplash

Scientists estimate that 95% of asteroids bigger than a kilometer have already been discovered and the remaining 5% are constantly being searched for in the sky for any threats they might pose.


Torino Scale

Researchers use something called the Torino Scale to categorize threats of meteors up to 100 years in the future.

A rendering of an asteroid as it flies through space.

Source: NASA/Wikimedia Commons

The scale goes from 0 to 10, with 0 being no hazard to the Earth and 10 being a certain collision that will cause a global catastrophe. Currently, all known objects observed in the sky have a “0” rating, and the highest rating on the scale to date has been a “4.”


Impact Odds

It is estimated according to the Torino scale that a level 10 certain collision occurs every 100,000 years or so on average.

Dice rolling in the air and hit the surface.

Source: Alois Komenda/Unsplash

To put this time scale into perspective, the earliest human civilizations only invented writing around a little over 5,000 years ago.


How Likely Is a Big Impact Crater?

Given what researchers know about the threats of impacts, it should not be surprising that the formation of big impact craters is low.

A man shrouded in shadow throws dice into the air.

Source: Max Felner/Unsplash

On average, the Earth will experience the formation of a 12-mile impact crater once about every one million years.


Mysterious Holes

Sometimes impact craters are confused with other earth movements that are observed by researchers.

A whole in Siberia formed from warming melt.

Source: Rainmaker1973/X

In recent years, scientists have discovered strange crater-like sites in Siberia that have led to the formation of mysterious “holes.” 


Climate Change Melt

Experts have determined that the Siberian holes that were first observed in July 2014 and are related to the effects of climate change. These holes appeared suddenly over the course of days and locals reported they were quite large.

A person holding up a sign with a drawing of Earth in the center and "one world" written either side of it.

Markus Spiske/Unsplash

“Global warming is happening, and it’s exacerbated in the Arctic,” Carolyn Ruppel, chief of the U.S. Geological Survey’s Gas Hydrates Project, told NBC News. “And if this [the Siberian crater phenomenon] is what we think, that it’s related to permafrost thaw, It’s a very visible effect of what’s happening to the Earth.”


Never Seen Anything Like It

Ruppel told NBC News she had never seen anything like it and the study team blamed the unusually warm summers in 2012 and 2013.

A shooting star falling from the sky.

Source: Chris Henry/Unsplash

Given the rarity of the formation of new meteor impact craters, people might get more used to seeing mysterious crater holes formed from the results of increasingly warm summers in places like the Arctic.