Volcanoes

1902 Ash flows active volcano Arenal bacteria basaltic birds blasts blow bubbles building called cloud cool Costa Rica cracks form Discovery Communications Donna O'Meara dust earth Earth's crust edges of plates explosion fluoride Garces gases happen hardens Hawaii Hawaiian Volcano Herculaneum hissing Hot magma hot spots Hydrogen sulfide Iceland Indonesia infrasound islands like Hawaii Italy Katia Katia Krafft Kilauea Krafft Krakatau Laki liquid living look magma flows Mark Twain melted rock Mexico miles Misenum Mount Vesuvius Mud flows mystery noise Novarupta Number ocean floor Pacific Plate pahoehoe plant plate subducts PLINY THE YOUNGER Pompeii pressure pumice pyroclastic fragments Ring of Fire Ruiz scientists sea floor shore sound Steve and Donna stratovolcano subducts sulfuric acid sun's rays Surtsey tall Tambora tectonic plates thick thicker thin Tsunami tubeworms up-and vent VIRTUAL VOYAGE volcanic activity volcanic eruption Volcanoes occur volcanologist wave worldwide temperatures