Fact check: Apparent 'grid pattern' of La Palma earthquakes due to data reporting methods

The claim: A “grid pattern” on a monitoring website shows La Palma island earthquakes are manmade

The volcanic eruption that began in mid-September continues on Spain’s La Palma island. The movement has also triggered earthquakes on the island, which is part of the Canary Island archipelago west of Morocco.

The quakes can be visualized using a web-based global earthquake monitoring platform run by the Euro-Med Seismological Centre. However, the appearance of the La Palma earthquakes on this platform – in a grid-like pattern – has led some social media users to claim the earthquakes are being technologically controlled or manipulated.

One video posted on Instagram showed users how to locate the grid pattern on the seismology website.

“These are the earthquakes that are happening on La Palma. They are in straight lines, in a grid pattern, folks. These earthquakes are being plotted out on a graph. And they are hitting exactly at specified coordinates over and over again in the same places,” said the video’s narrator. “This island is being manipulated by, it looks like, some kind of technology.”

The post, dated Oct. 24, was viewed more than 1,200 times in 12 days.

But it's wrong.

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The grid pattern is a result of data representation methods used by the website. It does not depict the actual configuration of the earthquakes, and it isn't evidence that the earthquakes are being artificially manipulated.

USA TODAY reached out to the social media user for comment.

The apparent grid pattern does not depict the actual configuration of the La Palma earthquakes

While encountering the grid may surprise a new user on the seismology platform, earthquake researchers say that it’s nothing unusual.

“The grid pattern... is common to see in some (earthquake) catalogues when zooming in on a small area with a lot of earthquakes,” Michael Floyd, a research scientist at the MIT Department of Earth, Atmospheric, and Planetary Sciences, told USA TODAY in an email.

The grid appears on the seismology website due to how the organization displays data, which Floyd said is perfectly adequate for most purposes.

Like any broad-scale global visualization tool, the web platform has spatial resolution limits. The La Palma grid pattern represents the intersections of lines of latitude and longitude where earthquake records are being grouped as the user zooms to those limits.

Even though there are actually earthquakes occurring at positions between the grid points, the seismology center is rounding those location values to the closest point of latitude and longitude that the platform processes.

“This is like taking a picture of a painting with a digital camera, and zooming into the picture too much,” Álvaro González a natural hazards researcher at the German Research Centre for Geosciences, told USA TODAY in an email. “One sees the squares – pixels – in the image, but they are not present in the original painting.”

The Euro-Med Seismological Centre website shows earthquakes around the La Palma volcano. The locations appear in a grid pattern due to resolution limitations. The dots don't show the exact location of each event.
The Euro-Med Seismological Centre website shows earthquakes around the La Palma volcano. The locations appear in a grid pattern due to resolution limitations. The dots don't show the exact location of each event.

Due to the interest the grid phenomenon has received, the seismology center posted a thread explaining the pattern on the organization’s Twitter page, @LastQuake.

The grid pattern can be observed across the website in areas where the user zooms in close on earthquakes occurring in a tight configuration, Rémy Bossu, a seismologist and secretary general of the seismology center, told USA TODAY in an email.

“The earthquakes are natural,” he said.

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On Oct. 31, a similar grid pattern could be found representing clusters of earthquakes in both Hawaii and Albania. However, whether a grid pattern is visible at a particular point depends on when users log on. The interactive map available on the website only records the previous 48 hours of data.

Volcanic eruption engulfs parts of La Palma
Volcanic eruption engulfs parts of La Palma

The La Palma earthquakes are naturally occurring, researchers say

There is nothing suspicious about the earthquakes associated with the La Palma eruption, González said. They are caused by accumulating magma breaking through layers of rock.

In the days before the eruption, earthquakes occurred as the magma rose closer to the surface. By tracking the pattern of the quakes, researchers were able to determine where the actual eruption would take place. This allowed local officials to evacuate nearby residential areas.

“Currently, this process of magma movement continues ... and still generates earthquakes as it breaks and shifts the rocks below the volcano,” González said. “Not only are these earthquakes natural, but they help us unveil the inner workings of volcanoes and forecast their eruptions.”

While the La Palma quakes are naturally occurring, induced seismicity is a real phenomenon. The United States Geological Survey has released multiple reports linking earthquakes with underground wastewater disposal from the oil industry. Similarly, an underground gas storage project off the coast of Spain is believed to have caused a spate of earthquakes in 2013.

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Shortly after the mid-September eruption of the La Palma volcano, USA TODAY debunked a false claim that the eruption could realistically catalyze a “mega-tsunami” that would impact the eastern U.S.

The narrator of the Instagram “grid” video made a connection between the two claims, saying the La Palma earthquakes were being manipulated to catalyze the mega-tsunami for political reasons.

Our rating: False

Based on our research, we rate FALSE the claim that a “grid pattern” on a global earthquake monitoring website shows the La Palma island earthquakes are manmade. As of Oct. 31, the grid pattern did appear on the seismology website, but it is merely a simplified representation of a large set of complex data. While induced earthquakes do exist, researchers say that the earthquakes on La Palma are caused by the geophysical process associated with the volcanic eruption.

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This article originally appeared on USA TODAY: Fact check: La Palma earthquake grid represents natural quakes