5 catastrophic megathrust earthquakes led to the demise of the pre-Aztec city of Teotihuacan, new study suggests

A chain of massive earthquakes may have led to the decline and eventual desertion of the pre-Aztec Mesoamerican city of Teotihuacan, a new study suggests.

Teotihuacan, which is located northeast of modern-day Mexico City and flourished between 150 B.C. and A.D. 650, had a population of more than 100,000 inhabitants at its heyday, but several centuries later that number plummeted substantially, according to a study published in the May issue of the Journal of Archaeological Science: Reports.

Researchers have long wondered what caused this dramatic population drop, with hypotheses including war and famine. However, a new analysis of some of the city's iconic pyramids reveals that Teotihuacan was hit by five treacherous megathrust earthquakes that shook the city roughly between A.D. 100 and 600.

"Megathrust earthquakes stand out as the most formidable seismic events ever documented," lead study author Raúl Pérez-López, an earthquake geologist at the Geological and Mining Institute in Spain, told Live Science in an email. "These earthquakes originate in subduction zones, such as the Middle American Trench (MAT) [an oceanic trench in the Pacific Ocean that's one of the world's largest subduction zones and the boundary between several tectonic plates, including the Nazca and North American]. What sets them apart is their extraordinary magnitude and relatively infrequent occurrence compared to other seismic events."

For example, one megathrust earthquake is so powerful that the seismic energy it emits "is equivalent to the energy unleashed by around 32,000 Hiroshima nuclear bombs," Pérez-López said. A more recent megathrust earthquake occurred in Japan in 2011.  

Related: 'Lost' 1,500-year-old Teotihuacan village discovered in the heart of Mexico City

"The release of such staggering energy during a megathrust earthquake can have catastrophic consequences for the surrounding regions, illustrating the immense destructive potential of these seismic events," he added.