Men search for people among the debris in a destroyed building in Adana, Turkey, Monday, Feb. 6, 2023. AP
Here's what to know about the quake.
The quake hit at depth of 11 miles (18 kilometers) and was centered in southern Turkey, near the northern border of Syria, according to the U.S. Geological Survey.
Many aftershocks have rocked the area since the initial quake. In the first 11 hours, the region had felt 13 significant aftershocks with a magnitude of at least 5, said Alex Hatem, a USGS research geologist.
Scientists are studying whether a magnitude 7.5 quake that hit nine hours after the main shock is an aftershock. Hatem said it appears to be the case.
``More aftershocks are certainly expected, given the size of the main shock,'' Hatem said. ``We expect aftershocks to continue in the coming days, weeks and months.''
WHAT TYPE OF EARTHQUAKE WAS THIS?
Researchers said the earthquake was a strike-slip quake, where two tectonic plates slide past each other horizontally, instead of moving up and down.
In this case, one block moved west while the other moved east _ grinding past each other to create the quake, Hatem said.
The quake occurred in a seismically active area known as the East Anatolian fault zone, which has produced damaging earthquakes in the past.
Turkey had another major earthquake in January 2020 _ a magnitude 6.7 that caused significant damage.
WHY WAS THIS EARTHQUAKE SO DEVASTATING?
The earthquake was powerful _ one of the biggest strike-slip earthquakes that has hit on land, Hatem said.
``On top of that, it's located near populated areas,'' she said.
Building collapses were reported in cities including Diyarbakir, Turkey, and Aleppo, Syria.
Rescue efforts were also hampered by freezing temperatures and traffic jams from residents trying to leave quake-stricken areas.