A geologic event known as diking can cause strong earthquakes with a magnitude between 6 and 7.
Diking can occur all over the world but most often occurs in areas where the Earth’s tectonic plates are moving apart, such as Iceland, Hawaii and parts of Africa in the East African Rift System.
As plates spread apart, magma from beneath the Earth’s surface rises into the space, forming vertical magma intrusions, known as dikes. The dike pushes on the surrounding rocks, creating strain.
Diking is a known phenomenon, but it has not been observed by geophysical techniques often. We know it’s linked with rift opening and it has implications on plate tectonics. Here, we see that it also could pose hazards to nearby communities.
The team investigated ties between two natural disasters from 2002 in the Democratic Republic of the Congo, East African Rift System. On Jan. 17, the Nyiragongo volcano erupted, killing more than 100 people and leaving more than 100,000 people homeless. Eight months later a magnitude 6.2 earthquake struck the town of Kalehe, which is 12 miles from the Nyiragongo volcano. Several people died during the Oct. 24 earthquake, and Kalehe was inundated with water from nearby Lake Kivu.
The Kalehe earthquake was the largest recorded in the Lake Kivu area. The geoscientists wanted to know whether it was coincidence that, eight months before the earthquake, Nyiragongo erupted.
Here the results in a paper entitled ‘Diking-induced moderate-magnitude earthquakes on a youthful rift border fault: The 2002 Nyiragongo-Kalehe sequence, D.R. Congo‘ by C. Wauthier, B. Smets, D Keir or the PennState news article: ‘Researchers find new cause of strong earthquakes‘