As of Tuesday, at least 7,300 people had been killed across Syria and Turkey following two massive earthquakes – the first a 7.8-magnitude, the second a 7.5 – that hit within the span of 10 hours on Monday.

Experts say the quakes are among the worst natural disasters to occur in the last century and the largest the region has ever experienced. The death toll is expected to rise as rescue efforts continue, officials warn.

“More aftershocks are certainly expected, given the size of the main shock,” Alex Hatem, a research geologist at the United States Geological Survey, told the Associated Press. “We expect aftershocks to continue in the coming days, weeks and months.”

The earthquake was caused by a “strike slip” along two huge tectonic plates, the Arabian and Eurasian, under Turkey’s southeastern provinces. Seismologists say a “strike slip” occurs when the plates are touching each other and then quickly slide sideways. The

The quake hit highly populated parts of both countries, wiping out entire city blocks in certain areas, according to BBC News. The region is ripe for such seismic activity, according to experts.

“Almost all of Turkey is really seismically active,” Eric Sandvol, a seismologist at the University of Missouri, said. “This is not something new to the country.”

Rescuers were able to retrieve a newborn baby girl from under the rubble of a building in northwest Syria that had been destroyed by the earthquake. The baby’s mother reportedly went into labor following the catastrophe and was able to give birth before she died. A family member said that the baby’s father, four siblings, and an aunt were all killed.

A search and rescue team, the United States Agency for International Development’s Disaster Assistance Recovery Team, or the USAID DART, is scheduled to arrive in Turkey tomorrow.