A couple of days ago, I felt some light tremors, checked the USGS site to discover the reason for the creaking house. The Salton Buttes volcano often has earthquake swarms, and this is one of them. What is interesting about this particular swarm, is that there has been two other swarms in the general area within a week and a half. There had been one a few miles to the south, and then one southwest near Ocotillo. Salton Buttes is a series of lava domes, and it still produces enough heat, that a nearby geo-thermal plant draws hot water and steam to drive it's turbines. The USGS lists this particular volcano as a possible volcanic hazard, should it some day decide to erupt. An eruption would effect Imperial County. Because the volcano is right next to the Salton Sea, an inland body of salt water, there is a risk of a water induced explosive eruption, if a certain type of lava came into contact with the salt water. There is a lot of rhyolite and obsidian around the volcano. When molten, rhyolite is a very slow moving and viscous lava. I went down there a few months ago and collected some of these rocks, and some tuff. In this video, I show these rock samples. There's more to come too!