The Hindu Kush range of mountains– which extends about 500 miles (800 kilometers) along the border of Afghanistan and Pakistan– shudders with more than 100 earthquakes at a magnitude of 4.0 or higher every year. The location is among the most seismically active areas on the planet, particularly for intermediate-depth quakes (tremblings forming in between 45 and 190 miles, or 70 and 300 km, listed below the world’s surface area). And yet, researchers aren’t sure why.
The mountains do not rest on a significant geological fault, where high earthquake activity is anticipated, and the area is lots of miles far from the slow-motion crash zone where the Eurasian and Indian tectonic plates are gradually clashing. So, what’s the handle this mountain earthquake epidemic?
According to the research study, the Hindu Kush mountains might owe their unbelievable seismic track record to a long “blob” of rock gradually leaking far from the variety’s below ground underbelly and into the hot, thick mantle listed below Like an only water bead retreating from the edge of a faucet, the 100- mile-deep (150 km) blob of mountain might be retreating from the continental crust at a rate as quick as 4 inches (10 centimeters) annually– and this below ground tension might be activating earthquakes, the authors of the brand-new research study composed.
The scientists found the problematic blob after gathering numerous years’ worth of earthquake observations near the Hindu Kush mountains. They saw that the quakes formed in a pattern, developing what appeared like a “round spot” of seismic activity in the world’s surface area, research study co-author Rebecca Bendick, a geophysicist at the University of Montana in Missoula, informed the site Eos.org Those quakes likewise formed along a clear vertical axis, starting in between 100 and 140 miles (160 and 230 km) listed below the continent, and were most typical much deeper down, where the strong continental crust fulfills the hot, thick upper mantle. Here, the scientists composed, is where the slowly-stretching blob is strained one of the most.
All of these observations followed a blob of strong rock gradually leaking into the gooey underworld listed below– a hypothesis that has actually formerly been utilized to describe comparable seismic activity below the Carpathian Mountains in main Europe According to the scientists, the Hindu Kush blob most likely started leaking no earlier than 10 million years back, and continues to extend down almost 10 times faster than the surface area of the mountains move, as the Indian and Eurasian plates clash.
If precise, these outcomes might be more proof that geophysical forces beyond simply the subduction of tectonic plates can send out earthquakes rattling through the world. As it was finest put in 1958: Be careful of the blob
Initially released on Live Science