Early Monday morning, a magnitude 7.8 earthquake ripped by means of Turkey and Syria, adopted 9 hours later by a 7.5 aftershock. The demise toll stands at more than 3,800, and rescuers have solely simply begun to comb by means of the collapsed buildings. 

Aftershocks will proceed to shake the world as native faults modify to such an enormous preliminary tremor, and scientists say that course of may proceed for not simply days however months and even years. There’s even an opportunity—albeit a small one—of an aftershock larger than the unique quake. 

“The aftershock risk is greatest, essentially, right after the mainshock, but there will be noticeable aftershocks to this earthquake for years afterward,” says David Oglesby, a geophysicist at UC Riverside. “Right now, I can forecast for you that there will be many more aftershocks of magnitude 5, probably 6 or so, in this area. That’s an easy call to make, because historically speaking, statistically speaking, that’s almost guaranteed.”

That will flip a humanitarian disaster in Turkey and Syria into one thing much more terrible. “We can’t say to people: OK, it’s good, you’re done. That was terrible, and it’s over now. Because that’s just not how the earth works,” says earthquake geologist Wendy Bohon. “It just really sucks to know that these people are going to have to continue to feel shaking from earthquakes for a long time, after they’ve been so traumatized and gone through such a devastating experience.”

Earthquakes are merchandise of plate tectonics: Plates are nice lots of rock that transfer independently within the earth’s crust, however contact one another alongside faults. “Eventually, the stress and strain is going to overcome the friction that is holding the rocks together, and those rocks are going to break in an earthquake,” says Bohon. “When the rocks break, they release energy in the form of waves, and those waves are what we feel as shaking.”

The mainshock Monday morning struck alongside some 125 miles of the East Anatolian Fault, a well known fault line in southern Turkey. Specifically, this was a strike-slip earthquake, which means stress constructed up between two lots of rock shifting horizontally in reverse instructions till the fault ruptured. It was additionally very shallow underground, which means it created extra intense shaking on the floor. (The San Andreas Fault in California can also be a strike-slip fault—that was the one which destroyed a lot of San Francisco in 1906.)

Generally talking, the bigger the mainshock, the bigger the aftershocks, which are likely to lower in frequency and severity as time goes on. As you may see in this map, aftershocks of assorted intensities have been swarming alongside the unique quake’s fault line in addition to at a unique however related fault line to the north, the place the magnitude 7.5 aftershock appears to have hit. “This is a really complicated system of faults, since the crust is really crushed there,” says Alice Gabriel, a seismologist on the Scripps Institution of Oceanography.

That complexity implies that what occurs in a single fault doesn’t keep there. It might have been that the stress that led to the 7.5 quake had been constructing for a while, and the jolt from the mainshock unleashed it. “It sort of advanced its clock a bit, so that it had the large earthquake that it would have eventually anyway, probably a bit sooner,” says Austin Elliott, an earthquake geologist on the United States Geological Survey. Such aftershocks are “just simply other earthquakes—there’s nothing that makes them distinct. It’s just that an earthquake so large changes the stress in the earth’s crust so substantially that it increases the rate of all other earthquakes locally.”