Japan and Ecuador earthquakes: Why does it feel like there are so many tremors and are they connected?

There are good reasons that the two deadly events feel like they might share a cause – but it is simply a rare coincidence

(AP)

Two different countries have been struck by deadly earthquakes – but there is no reason to think they’re connected.

The two earthquakes, just hours from each other, killed hundreds of people in Japan and Ecuador on Saturday. But they happened thousands of miles apart, and though it seems like there could be a connection and an increasing incidence of tremors, there is no connection between the two events.

The Japan and Ecuador earthquakes happened close to each other in time but almost 9,000 miles apart. They also happened for different reasons, and there is no connection between the causes for either earthquake.

The earthquakes have however been connected to other tremors in the region, a phenomenon that is likely to continue in the coming days. Those events definitely are connected, with aftershocks and foreshocks arising from the main tremor.

Other similar problems will hit the regions in the coming days, too, as authorities in both countries have warned of the potential for landslides caused by the seismic activity.

The two countries also both sit on the “Ring of Fire” that stretches around the Pacific Ocean and leads places within it to be more at risk of earthquakes – around 90 per cent of earthquakes happen in that area. While there is no connection between their causes, both areas are more at risk of tremors because they each sit on top of colliding major tectonic plates.

But the main earthquakes are a rare coincidence of two independent – and rare – events.

Earthquakes that are between magnitude 7.0 and 7.9, like those that hit Japan and Ecuador, happen about 15 times per year, on average. That means that it’s unlikely that two will happen on the same day – but far from impossible.

And the events happen entirely independently of each other. Earthquakes might happen close together but also far apart – last year, there was no earthquake over a magnitude of 7.0 between 27 July and 16 September.

It might feel like there are more earthquakes in general because there is more reporting of them – our instruments mean that we’re more likely to spot an earthquake, and the increasing use of the internet and media around the world means that they are more likely to be reported when they happen.

In the case of the Ecuador and Japan earthquakes, both happened in especially well-connected and highly-covered areas. Earthquakes regularly happen in sparsely populated areas – and often under the sea – which means that they might not even be spotted, and are unlikely to do substantial damage if they do.