Posted tagged ‘Earth science’

What makes an earthquake “swarm”?

November 4, 2009

Reno, Nevada may be known as a popular gambling destination, but it is also the site of thousands of earthquakes that rocked the city last year. Scientists call the mysterious quakes a “swarm,” but what causes them is unclear – and the term itself is a bit ambiguous. In fact, my first question upon assignment to the project was, “What exactly is a swarm?”

There is no precedent for the growing frequency and intensity of the earthquakes in Reno last year. Unlike a typical mainshock-aftershock earthquake sequence, the Reno earthquakes struck with increasing magnitude hundreds, even thousands of times over a period of less than one year. Over the course of ten days, our crew questioned seismologists, geodesists and emergency responders for answers as to why this phenomenon occurred. Their insight into potential causes of the earthquakes astonished me. But I still couldn’t conceptualize just what a swarm is–-what hundreds of small earthquakes hitting every day must have felt like.

Fortunately, my confusion cleared up on the last day of our shoot. And ironically, it wasn’t a scientist who provided the answer. While sitting on a dusty slope of the Sierra Nevada Mountains, I asked our Production Assistant, a student at the University of Nevada in Reno, “How would you define the swarm?” Her explanation was a real eye-opener: “It was like someone playing a drum nonstop. You couldn’t hear the beats, but you could feel the vibrations.”

Katherine de Gaullier des Bordes, Associate Producer

Naked Science: Reno Earthquake Swarm

Naked Science: Earthquake Swarm airs Thursday, November 5th at 10PM/9C on National Geographic Channel