Why Peru's M8 Earthquake Was Damaging, but Not Catastrophic
Not all magnitude 8 earthquakes are created equal. Find out what separates merely devastating from completely catastrophic.
By Dana Hunter on May 31, 2019
Why Peru's M8 Earthquake Was Damaging, but Not Catastrophic
Detail of the Peru 2019 earthquake USGS shakemap Credit: USGS
In August of 2007, a magnitude 8 earthquake struck the central coast of Peru, killing 519 people and injuring nearly 1,500. Tens of thousands of homes were destroyed, and a tsunami up to 5 meters high flooded the Pisco shore and the Costa Verde Highway.
On May 26th, 2019, a magnitude 8 earthquake struck Peru just east of the Andes. Falling debris killed two people, and at least 30 more were injured. Many old houses collapsed, a bridge or few fell, and some roads were blocked, but the damage was far less severe than in 2007.
Both quakes were caused by the Nazca plate subducting beneath the South American plate. It's moving east at roughly 70mm per year in this area. So why would one quake case hundreds of deaths and catastrophic damage to a large area, and another quake of the same magnitude on the same plate cause so little?
Zooming out, we see a plate boundary extending 7000 kilometers, pushing up the Andes, giving birth to volcanoes, and causing frequent huge earthquakes. But not all of those earthquakes happen at the same distance from the trench or at the same depth. And that matters a lot when it comes to how devastating a large-magnitude quake will be.
More:
https://blogs.scientificamerican.com/rosetta-stones/why-perus-m8-earthquake-was-damaging-but-not-catastrophic/?redirect=1
Science:
https://www.democraticunderground.com/122864232
