Pointers to Review * Phreatic Eruption * is a stream-driven eruption as the hot rocks come in contact with water. It is shortlived, characterized by ash columns but may be an onset of a larger eruption. Shown on the right is our Taal Volcano in Batangas. * Phreatomagmatic Eruption * is a violent eruption due to the contact between water and magma. As a result, a large column of very fine ash and high-speed and sideway emission of pyroclastics called base surges are observed. * Plinian Eruption * excessively explosive type of eruption of gas and pyroclastics, just like our Pinatubo Volcano in Zambales. * Altitude * the height above sea level. * Constellation * A constellation is a group of stars that, when seen from Earth, form a pattern. The stars in the sky are divided into 88 constellations. * Volcanic Ash * Volcanic ash consists of fragments of pulverized rock, minerals and volcanic glass, created during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. * Active Volcanoes * are those that have a record of eruption within the last 600 years or those that erupted 10, 000 years ago based on analyses of their materials. * Inactive Volcanoes * are those that have not erupted for the last 10, 000 years and their physical form is being changed by agents of weathering and erosion through formation of deep and long gullies. * Extinct Volcanoes * are those that scientists consider unlikely to erupt again, because the volcano no longer has a magma supply. Examples of extinct volcanoes are many volcanoes on the Hawaiian

* Types of Volcanic Cones * Shield volcanoes - are formed by the accumulation of lava that oozes out from the volcano. Since non-viscous lava can flow freely, a broad, slightly domed structure that resembles a warrior’s shield is formed. Example of