Both types of structures are preserved in geyserite, a type of rock that is only found in and around freshwater hot springs in volcanic areas on land. (newscientist.com)
This is one of 26 natural reserves in the Garrotxa Volcanic Area Natural Park. (unalomeyogaretreats.com)
In recent years, seismologists have realized that the biggest quakes can trigger more quakes thousands of kilometers away, but these are typically small and often located at hot springs or volcanic areas already prone to small quakes. (sciencemag.org)