Natural Disasters Volcanoes PDF

Volcanos Catestrophic Summit Collops 10. &M 24.. Has a raret huge RI , ↳ example : Crater L...

Volcanos Catestrophic Summit Collops 10. &M 24.. Has a raret huge RI , ↳ example : Crater Lake , OR Some Examples of Caldera 1 ) Crater. Lake-still active volcano 2 ) Krassatau..) Santorini 3 Crater Lake : Krakatav , Indonesia , 1883 - Is located between Java and Sumatra - Volcano cavesed an Tsunami recently erupted in a pyrolastic erruption - - A cinder come inside the strato edifaces Santorini 1630 BCE - Plato wrote an descriptions , lost continent of Atlantis ? - Is at an subduction zone. A Controlls Santorini - The country of Greece is very tectonically active - City of Reno occanic hot spot Hawaii A hot spot of a mantle plate that raises Mauna Kea is the tallest volcano I has space equipment built bl , it is not actively on the hot spot. Only 2 volcanoes active on Big Island , 2 Shield volcano 1) Kilavea 2) Mauna loa low viscosity , bic low silica - Short RI high Frequencey  Deadliest Volcano Hazard 10. 24. 24 Most Dangerous = pyroclastic Flows & Volcanic Mudflows ↳ can Strato Volcanos only occur at - Mudflow instead of mudslide by mud flows Pyroclastic Flow-Nuee Ardente (glowing cloud scalding avalanche of ash ↓ toxic , expanding gases - Fast speed down Volcano Flank - Travels 140-200 kmh - 2 ways to produce pyroclastic flow : Il column collapse : Follows explosive eruption. 2.) Dome collapse : Follows collapse of the dome. Moves down the sides of Volcano , destroying everything in its path. Dome collapse can ocurr wout an erruption - Mt. St Helens is a pyroclastic flow of column collapse - Dome collapse example = Mt unzen Japan , ↳ active Still Volcanic Mudflow-Lahar * rapid flood of pyroclasts & water. Water can be provided by : · rainfall on loose as snowdice show melting of volcanos · cap , on · Breakout of Lake on Crater · Rivers a lates near the volcanos - Cooler than pyroclastic flow, A torrent of mud pyroclasts boulders. , , has to have water to ocurr or it would not be a mud flow. - Mudflow is mostly water - Moves fast , not as fast as pyroclastic 10 24. Volcanos : Strato-volcanoes : Subduction Four events : Mt. St Helens,. Mt Pelle, Nevado Del Ruiz , Mr Vesuvius Mt St Helens WA 1980 Case Study #... , - Occurs at the subduction on the Juan de Fuca subducting under the North American plate : Cascadia Subduction Zone. ↳ Active volcanos despite stuck plate - RI = 200 - 250 yrs Cascade volcanos are strato volcano - Was a plinian eruption * Precursors can allow us to predict earthquakes A Precurso Events : & Frequently - Swarms of E Q.. occurs through the North -Steam/ash eruptions T Mt. St Helens has budge errupting sideways that geologists -. didn't expect - Main (VEI : 5) ervation Mt. St Helens. 10 29.. 24 gigantic landscape - mudflows - Steam Blast (500 K/h) - The volcan happened with a Mag S earthquake and was a Volcano earthquake not plate tectonics , and caused mudflow a landsli - Plinian column wh pyroclastics Flow by steam blasts. X Everything was destroyed at Spirit Lake Fully , grown trees were destroyed by steam blasts. St Helens is Mt.. not catastrophic Summit collapse it , is a normal eruptions that went north sideways. 57 people died. Spirit Lake & melted ice caused mud flow Landslide caused roofing of the Volcano , steam blast overtook landslide. composition of eruptions Intermediate Andosiote = , geologist David Johnson was under steamblast t was killed - ↳ cascades Volcano Observatory was named after him at Johnson Ridge  Mt. St Helens. 10. 29. 24 Victims : - Harry Truman had a cabin on Spirit Lake for 50 years and ignored the authorities who told him to evacuate who refused to leave I was killed also has Harry ridged named after him Wildlife was also displaced or killed. - Zyrs after eruptions a lava dome can collapsed and cause a pyroclastic eruptions but never erupted again Volcanic case Study #2 : Mt. - Pelee ma , Caribbean Atlantice sea floor subduct on the Caribbean Plate , in between North A. Plate. ↳ The caribbean plate moves east the North American plate subduct moves. west Volcano occurs on Martinique islands , City of. Pierre St was most affected Volcano gave signs that it was going to erupt. ↳ precursor Mild E Q + ash/steam eruptions =. There was elctions and the city officials wanted votes they sent a small comittee of teacher sent and told officials nothing was happening on the volcano I told the city the volcano was fine. - 3 day before eruptions invasion : of red ants, snakes - The eruptions was pyroclastic flows , Death foll = 30 ,000. Whole town of St. pierre was destroyed only 2 Survivors : A ten year old girl who hid in the cave under the volcano t a prisionors who put in a dungeon jail & survaior escaped jail and was ↳ Prisionor = Louis Auguste Gyparis (Was found 3 days after. 1903 tower of Pelee lava dome grew inside volcanot generated , flow pyroclastic Case Study #3 : Nevado del Ruiz 1985, Colombia Nazca Plate South America plate subducting under - strato volcano - The volcano is in the Ands a had, ontop which creats risks snow of lahor , it was also raining ask and buried the city of Armero in a lahar mud flow. The City of Armero is at the canyon of the volcano , the city was destroyed by Lahar first in 1800s.  Volcano 10 29.. 24 Case Study #3 : Nevado del Ruiz 1985, Colombia. cont Precursors : small harmonic E. Q. & steam eruptions representing the magma raising There was no evacuation , City officials didn't think it was worth it. ↳ lahar bk the ice geologist told journalists that there was a 100 % of a on top of volcano. The rain caused more water to add to labar VEl: 3 - The lahars buried Armero Death toll : 25, 000 Scientiest who suggested evacuations were forced by the government to leave bic they were disrupting social order f the journalist were forced to remove the geologists recommendation of evacuation from the newspaper by the government - Children were not Found, Los ninos de Armero ↳ Omaira Sanchez Survived 3 days later but was stuck in lakar a died. Case Study #4 : Mt. Vesuvius 79 GE Italy Subduction trench Italy The Mediterrain trough. sea floor subduct - ing under Europe volcano erupted again in 1940 during WWI Cities of Pompeii & Herculaneum were buried a most affected Cities maybe Pompeii is thought to be a population of (20 000.) ↳ , Pumice ash fall t pyroclastic flows mudflow (most , deaths) - RI: low , 2, 000 years (is due to erupt again on the same scale) - Eruption opened a Caldera People currently living on the flank of the Volcano, people build on the site of lava flow caused from Column plinian collapsed pyroclastic - - An inner crater inside the Caldera has been building since the eruptions. Eroclamor Portici is built on Herculaneum currently - ash cooling creates body case a shapes of people The volcano erupted for 2 days the 2nd day was pyroclastic flow which killed most people.  Landslides Mass Wasting 10 31.. 24 Outline: Mass wasting · · Factors · Types · Triggers · Coastal Erosion Mass Wasting : Downslope movement of rock/sed/ soil under the influence of gravity 2 Forces : Friction ↳ gravity , (Slope-resisting force , Slope · Failure > - gravity > - Friction Mass wasting is correlated to plate tectonics indirectly Factors in Mass Wasting: 1. ) Water content (Most Important cause) ↳ excess water increases slope failure..) 2 Slope angle ↳ Steep slopes increases slope Failures 3) Geological ↳ tilt of rocks layers , type of rocks , clay ↳ loose sediments erodes more 4) Human ↳ Overloading of slopes , artificial filly , excavation of highways deforestation 5) Vegetation : - decrease slope failure, roots system removs water a stabalizes Which One is more dangerous : B , away from the land A Sliding towards the ocean. ~ L  Landslides MassWastg 10 31 24 sing :.. · Falls. Slides , flows Rockfall : - Jointed rocks fall, free fall of rocks , very rapid common in mountains - Rock dislodged from parent rock ↳ can cause avalaches or small tsunamis. Retaining wall prevents rock from falling onto cars + Street. ↳ also built bridges to go through Rock Slide : 2 types Slump & Slide - ↳ Is typically larger than slump - The movement of rock layers down a failure surface. A Slump-Rotational Slide : ·. · Curved surface , of ruptueweak sediments small ↳ usually leaves a scare , looks like faults ↳ can becaused by uplift by faults wi restring bend B. Rockslide - Transitional Slide : Planar surface more Coherent , deadlier is typically leaves still alive d a scare ↓ Vegetation growing. ↳ Slope in same direction as cliff can be more likely to fail Rockflows : Movement as a Viscous fluid , 4 types of flows, Critical component = water. A) Mudflow-most fluid , common ; heavy rain storms ↳ NOT Mudslides B) Debris Flow/avalanche largest - , fastest ; very deadily I rare , high reocurrence interval C) Lahar-Volcanic mud/debris flow , containg a lot of ash water D) Creep-slowest , most commona widespread , least dangerous ↳ tilting ground  Landslides Mass Wasting 10 31.. 24 - Mudflow-moving from conslidatio onto valleys a areare Triggering External factors that allow rocks to Fail Events & - 1. ) Rainstorms (Most common)-Venezuela Most to least common.. ) Earthquakes 2 E Q Northridge.. 3) Volcanoes - example: Mt St.. Helenes Clandslide (1999) - Example: Most deadliest , Venezuela , huge debris flow /Floods Cheavy rain) ↳ la Conchita 1995 + 2005 Coastal Erosion & Collapse : Sandstone a sediments have high erosion risks - Rockfall-Cliff Structure uniforma horizontal planes - Rock Slide-Rock - wave energy : causes notches Wave cut notch -.