CSSCI02 4TH Q

• Volcano - derived from the word “vulcan” which is an island in Italy and/or the God of Fire in the Roman Mythology.
• Volcano - is an opening in the earth's crust through which molten lava, ash, and gases are ejected. It is generally located in areas where the tectonic plates diverge or converge with each other.
• SHIELD VOLCANO - type of volcano built entirely or mostly from fluid lava vents. It can measure for about hundreds of miles across and many tens of thousands of feet high.
• CINDER CONE VOLCANO - normally small about a miles span and about one thousand feet vertically. Cinder cone volcanoes consist of mostly loose, grainy cinders and have very little to no lava.
• COMPOSITE VOLCANO - also called “Strato Volcano.” Composite volcanoes consist of lava that is mixed with sand or gravel which in turn creates cinders or volcanic ash.
• CALDERA "GIANT" VOLCANO  - Caldera volcanoes are circular depressions in the ground over a magma chamber. This type of volcano is easier to notice from space due to the distance and viewpoint.
• FISSURE VOLCANO - Fissure volcanoes have no main crater, the ground just splits and lava pours out through the cracks. They are also hard to recognize from the ground and sometimes from space.
• Active volcano - An active volcano is a volcano that has had at least one eruption during the past 10,000 years. Active volcanoes are the type of volcanoes that in general have been active for a certain period of time.
• Dormant volcano - Dormant volcanos are the that are quiet volcanoes, but might possibly erupt again
• Extinct volcano - Volcanoes are often considered to be extinct if there are no written records of its activity.
• HAWAIIAN ERUPTION - fluid basaltic lava is thrown into the air in jets from a vent or line of vents (a fissure) at the summit or on the flank of a volcano.
• STROMBOLIAN ERUPTION - eruptions involve moderate bursts of expanding gases that eject clots of incandescent lava in cyclical or nearly continuous small eruptions.
• VULCANIAN ERUPTION - a short, violent, relatively small explosion of viscous magma.
• PELEAN ERUPTION - associated with explosive outbursts that generate pyroclastic flows, dense mixtures of hot volcanic fragments and gas.
• PLINIAN ERUPTION - They are caused by the fragmentation of gassy magma and are usually associated with very viscous magma.
• ICELANDIC ERUPTION - from small effusive eruptions where lava flows quietly from fissures and crater rows to significant explosive eruptions in ice-covered central volcanos that produce large ash plumes
• A tsunami, a term which originated from the Japanese “tsu”, which means harbor, and “name”, which means wave, is a series of waves generated when an oceanic body of water is rapidly disturbed because of an underwater earthquake, volcanic eruption, landslide or underwater explosion, and whose height could be greater than 5 meters
• Remember that tsunamis are generated by earthquakes and tsunami waves are generated because of movement of fault under the sea. It have nothing to do with high tide and low tide which is caused by the gravitational pull between the earth and moon. The increase in wave heights associated or during typhoons (when there are strong winds) or tropical cyclones are called storm surges
• Local tsunamis - are confined to coasts within a hundred kilometers of the source usually earthquakes and a landslide or a pyroclastic flow. It can reach the shoreline within 2 to 5 minutes. 
• Far field or distant tsunamis - can travel from 1 to 24 hours before reaching the coast of the nearby countries.PTWC (Pacific Tsunami Warning Center) and NWPTAC (Northwest Pacific Tsunami Advisory Center) are the responsible agencies that closely monitor Pacific-wide tsunami event and send tsunami warning to the countries around the Pacific Ocean.
• According to the Philippine Institute of Volcanology and Seismology (PHIVOLCS), there are 3 natural signs of an impending tsunami: SHAKE (earthquake), DROP (water recede or rise), and ROAR (unusual sound).
• Feel an earthquake.  If the ground shakes under your feet in a coastal region, a tsunami may have been caused by a strong undersea earthquake. However, you may not feel an earthquake if the event is far away. 
• See ocean water disappear from the beach, bay or river. Before a tsunami arrives, water may recede from the shoreline before returning as a fast-moving wall of water. If you notice the water is disappearing, tell your family and friends and prepare to move inland or to higher ground.
• Hear an unusual roaring sound. If you hear a loud roar approaching (a bit like a passenger jet or a train), tell your family and friends. It could be a tsunami approaching.
• Official signs of a tsunami are (1) Outdoor tsunami warning sirens and messages, (2) Emergency alert phone calls and text messages, and (3) Television and radio warning broadcasts.
• When you get a warning, go immediately to high ground: 50 feet or more above sea level.
• Soil erosion is a gradual process that occurs when the impact of water or wind detaches and removes soil particles, causing the soil to deteriorate. Soil deterioration and low water quality due to erosion and surface runoff have become severe problems worldwide.
• A landslide is a movement of earth, rock, or debris due to gravity. Landslides can be caused by continuous heavy rainfall, strong earthquakes, or human activities.
• A landslide is a massive outward and downward movement of slope-forming materials, it is restricted to movements of rocks and soil masses. These masses may range in size up to entire mountainsides. Their movements may vary in velocity.
• Rotational Slides - move along a surface of rupture that is curved and concave
• Translational Slides - occur when the failure surface is approximately flat or slightly undulated
• • Rock Fall Free falling detached bodies of bedrock (boulders) from a cliff or steep slope
• Rock Toppling - occurs when one or more rock units rotate about their base and collapse
• Debris Flow - Down slope movement of collapsed, unconsolidated material typically along a stream channel
• Lateral Spreading - occurs when the soil mass spreads laterally and this sp[reading comes with tensional cracks in the soil mass
• Earthflow - Earthflows exhibit an hourglass shape, with slope material liquefying and flowing downhill, forming a depression at the top.
• • Creep refers to the slow, continuous downhill movement of soil or rock due to shear stress, causing permanent deformation without reaching shear failure.
• New cracks - or unusual bulges in the ground or street pavements
• Steep Slopes: slope with angles over 30 degrees should be avoided if possible
• Gravity - works more effectively on steeper slopes