The massive blast from a fertilizer plant in West, Texas imprinted an unmistakable signature underground and in the atmosphere.
Up to 15 people are feared dead and at least 160 injured from the explosion that leveled homes and businesses Wednesday evening.
Under the surface, the blast registered as a 2.1 magnitude earthquake according to the U.S. Geological Survey (USGS) website. The USGS said it shook houses 50 miles away. It was initially classified as “Quarry Blast” due to its seismic effect.
The USGS revised the classification to simply “explosion”, commenting that the underground shaking was not a true indicator of the blast’s potency.
“[The 2.1] magnitude measures only the ground motion, not the air wave, so is substantially less than the true size of the event,” USGS said on its website.
A seismometer recording in West, Texas not only picked up the ground waves, but also the subsequent sound wave that resonated through the air.
So powerful was the explosion that a seismograph in Amarillo, Texas, over 400 miles away, detected it.
— Jason R. Hunter (@coreburn) April 18, 2013
Skyward, infrared satellite imagery sensed a hot spot from the blast, as indicated by the yellow enhancement co-located with plant site.
The frightening video below provides a sense of the magnitude of the explosion (caution: one expletive is audible towards the end.)