Utah's examples of cinder cone volcanoes are Black Rock Volcano and Veyo Cinder Cone near St. George. Composite or Strato volcanoes are somewhere in between the shield and cinder cone volcanoes. They are formed by the buildup of alternating layers of lava, ash, cinders, and blocks. Mt. St. Helen and Mt. Vesuvius are examples of strato volcanoes. In Utah, the Tushar Mountains, including Mount Belknap, are examples of composite volcanoes.
Volcanoes also have a positive effect.
They add water vapor to the atmosphere and the eventual breakdown of lava enriches the soil. Volcanos also form spectacular mountains. Earthquakes Earthquakes are sudden movements in the earth's crust caused by a release of energy when blocks of rocks within the crust move along a crack in the crust called a fault. Much of the material written about earthquakes refers to movement along plate boundaries. However, earthquakes occur in the middle of plates as well.