Earthquakes
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Earthquakes Presentation Transcript

  • 1. EARTHQUAKES AND VOLCANOES Presented To: “Miss. Huma Naeem” By: Muhammad Saghir(004) Sumbal Zahid(013) Ayesha Siddiqa(017)
  • 2. WHAT IS AN EARTHQUAKE AND VOLCANO? Moment of Crust Rupture of Crust
  • 3. FORMATION OF EARTHQUAKE Two blocks of the earth suddenly slip past one another. Terms related: • fault plane • hypocenter • epicenter • foreshock • mainshock • aftershocks
  • 4. TYPES OF EARTHQUAKE Three main types of fault that may cause an earthquake. • Normal • Reverse • Strike-slip
  • 5. Lithosphere of Earth is broken into plates • Study of movement and interaction of plates: Plate Tectonics • • • • Zones of plate-edge interactions are responsible for most earthquakes, volcanoes and mountains Divergence zones – Plates pull apart during seafloor spreading Transform faults – Plates slide past one another Convergence zones – Plates collide with one another The tectonic plates of the world were mapped in the second half of the 20th century
  • 6. Earthquake Hazards • Ground shaking • Tsunamis • Landslides and Rockfalls • Subsidence and lateral spreading • Liquefaction
  • 7. TSUNAMIS TSUNAMIS CAN BE GENERATED BY: • Large Earthquakes (megathrust events such as Sumatra, Dec. 26, 2004) • Underwater or near-surface volcanic eruptions (Krakatau, 1883) • Large landslides that extend into water (Lituya Bay, AK, 1958) • Large undersea landslides (evidence for prehistoric undersea landslides in Hawaii and off the east coast of North America
  • 8. FORMATION OF VOLCANOES Chemical composition (largely silica dioxide sio2 - content) And Gas content (largely water vapor and co2). Sio2 content controls the viscosity of a magma. The greater the viscosity the more gas in the magma. There are three basic types of magma: Andesitic Rhyolitic Basaltic Magma Magma Magma
  • 9. Magma Type Basaltic Chemical Composition Temperatur Viscosity e (degrees C) 45-55% SiO2; 1000 - 1200 High in Fe, Mg, Ca; Low in K, Na. Andesiti 55-65% SiO2; 800-1000 c Intermediate Fe, Mg, Ca, Na, K Rhyolitic 65-75% SiO2; 650-800 Low in Fe, Mg, Ca; High in K, Na Low Gas Content Low Intermediat Intermedia e te High High
  • 10. TYPES (ON BASIS OF ERUPTION Large amounts of gas and a Small amounts of gas and low viscosity (runny) magma will form high viscosity (sticky) an effusive eruption magma will form an explosive eruption  Where the magma just trickles out of the volcano (lava flow).  Think about shaking a carbonated drink and then releasing the cap.
  • 11. 3 States of Volcanoes:  Extinct Volcanoes e.g. Zuidwal volcano in the Netherlands, Emperor seamount chain in the Pacific Ocean etc.  Dormant Volcanoes e.g. Kilauea (Hawaii) Mt. Etna (Italy)  Active Volcanoes e.g. Mauna Loa etc. Fourpeaked volcano, Alaska, in September 2007, after being thought extinct for over 10,000 years
  • 12.  Composite  Cinder Cone  Shield • • • • • • • • Mt. Rainier, Washington Tens of miles across and ten thousand or more feet in height. Tall cone shaped. High in silica High viscosity magma High levels of gas Highly explosive. Formed by layers of lava and ash. Caused by viscous magma. Actually, a mix of basaltic and rhyolitic magmas in many cases.
  • 13. Mt. Fuji, Japan Mt. St. Helens, Washington • After an eruption a large caldera remains. • Crater lake is a caldera that remains following an explosive eruption 7,700 years ago • The eruption was 42 times more powerful than Mt. St. Helens.
  • 14. SHIELD VOLCANOS • Huge in size • A broad shaped, gently sloping cone is formed, but have low slopes. • Flattened mound • Resembles a warrior’s shield. • Low silica level. • Dominated by fluid, high temperature, low viscosity basaltic magma • High or low levels of gas. • No pyroclastic material. This makes the eruption relatively safer.
  • 15. Muana Loa Volcano – the world’s largest volcano. Photograph by J.D. Griggs on January 10, 1985 • • Over 30,000 feet above sea level. Most active and planet's largest volcano
  • 16. • • Relatively cool basaltic magmas or andesitic magmas predominate.. • Low silica lava • “Fire-fountain” eruptions • Commonly found on the flanks of shield volcanoes Steep conical hill formed above a vent. • • Structurally weak. • gaseous magmas. Small volcanoes. • Dominated by viscous, Range from several meters to over 300 m in height • • Circular or oval cones. Made from a pile of rock pieces Mount Edziza, British Columbia
  • 17. Puu OO, Hawaii Pu'u ka Pele, Hawaii (on the flanks of Mauna Loa) Floreana Island, Galapagos
  • 18. Lava domes • Lava is too viscous to flow to a great distance. • Lava pile within. • When a lava dome is grown to a significant extent, it shatters the outer surface, which results in spilling loose fragments towards its sides. • Found on the flanks of larger composite volcanoes.
  • 19. Volcanic Hazards • • Ash flow • Land sliding • Noxious Gas • flows down slope. Lava flow • and other volcanic debris that Pyroclastic fall • Water saturated slurry of ash Lahars/Mud flows • LAHARS Pyroclastic flow Earthquakes
  • 20. Pyroclastic Flow: • A pyroclastic flow is a fastmoving (up to 700 km/hr) extremely hot (~1000°C) mass of air and tephra that charges down the sides of a volcano during an explosive eruption. • Cinders. • Ash and dust. Pyroclastic flow at Mount St. Helens, Washington, August 7, 1980.
  • 21. Volcanic ash fall during mid-day with the eruption of Mount Pinatubo in the Philippines. Pahoehoe: Lava with a ropelike surface texture due to partial cooling as the lava flowed. Relatively hot, low viscosity lava. A hot, gaseous cloud of ash that flows down slope Flow speeds can reach 160 km/hr and temperatures can exceed 600 degrees C.
  • 22. WORLD WIDE EARTHQUAKES AND VOLCANOES • 2010 Chile earthquake. • Magnitude of 8.8. • Is at a convergent plate boundary that generates megathrust earthquakes. Railway track disturbed by Earthquake.
  • 23. • Fault between the pacific and north American plates ruptured. • • Shifts created large tsunamis (u p to 220 feet (67 m) in height. • Alaska Earthquake 1964 Liquefaction. Losses The number of deaths from the earthquake totalled 131; 115 in Alaska and 16 in Oregon and California.
  • 24. Great East Japan Earthquake Effect Of Earthquake On Tokyo Tower. • • • • • • Nuclear and conventional power plants went offline. 1000 aftershocks. 15,882 deaths, 6,142 injured. 129,225 buildings totally collapsed, with a further 254,204 buildings 'half collapsed. • Magnitude 9.03 Undersea megathrust earthquake off the coast of japan. The quake moved portions of northeastern japan by as much as 2.4 m (7.9 ft) closer to north America, making portions of japans' landmass
  • 25. Mt. Fuji, Japan • A Stratovolcano that has erupted 16 times since 781 AD. • The most recent eruption was in 17071708 •0.8 cubic km of ash, blocks, and bombs were ejected during that eruption.
  • 26. • • • • Just southeast of Hawaii is an undersea volcano known as loihi Until 1996 loihi was thought to be an inactive seamount. It began erupting in 1996 and the eruptions were preceded by a cluster of small earthquakes indicating the movement of magma. The modern active island rests close to the hot spot and its shield volcanoes are fed from the magma that the hot spot generates.
  • 27. • • • • The Kilauea volcano erupted, with a fissure throwing lava up more than 20 meters towards the sky in a dazzling display of volcanic power • Lava 65 feet in the air. Sulphur oxide and other volcanic gases are continuing to erupt . Kilauea is the youngest volcano in Hawaii and could be the world’s most active volcano and has erupted 34 times since 1952. Has been erupting consistently since January 1983.
  • 28. Mount Pinatubo, Luzon, Philippines – 1991 • • • Stratovolcano. Explosive eruption. Ejected more than 1 cubic mile (5 cubic kilometers) of material into the air and created a column of ash that rose up 22 miles (35 km) in the atmosphere. Ash fell across the countryside, even piling up so much that some roofs collapsed under the weight. Nevado del Ruiz Volcano, Colombia—1985 • • • • Second most devastating volcanic eruption in the twentieth century. Result of a lahar. An ice-cap volcano. Ice melted and a huge flood. Boulders 32 feet-high still litter the landscape around Nevada del Ruiz
  • 29. NOVARUPTA, ALASKA PENINSULA – JUNE, 1912 • Largest volcanic blast of the 20th century • The powerful eruption sent 3 cubic miles (12.5 cubic km) of magma and ash into the air, which fell to cover an area of 3,000 square miles (7,800 square km) in ash more than a foot deep. • Caused global temperatures to drop by about 1 degree Fahrenheit (0.5 degree Celsius) MOUNT ST. HELENS, USA—1980 • • Large earthquake at 8:32 that morning measuring. 5.1 on the richter scale, • of ash rose up to 15 miles into the atmosphere. • $1 billion worth of damage to the lumber and agricultural industries.
  • 30. Iceland's Eyjafjoll Volcano: • Iceland’s largest volcanoes • A strato-volcano. • Dormant beneath the Eyjafjoll Eyjafjallajkull volcano glacier. • In year 1823, a fairly gentle eruption with some local flooding occurred • European air travel was severely Eyjafjallajkull Glacier disturbed • Eruption began on march 20th 2010, Ash coming out of the Eyjafjallajkull Volcano in the recent eruption that created havoc in European airspace
  • 31. Earthquakes in Pakistan • History has shown us that Pakistan is indeed situated near highly active fault line that could put risk to more than 170 million people living in the country.
  • 32. 1935 Balochistan Earthquake • • • Magnitude of 7.7 30,000 and 60,000 people died from the impact Deadliest earthquakes that hit South Asia. Camps can be seen during the post-1935 earthquake. 2011 Pakistan Earthquake • • • Magnitude of 7.2 rocked southwestern Pakistan. At sparsely populated areas thus was not disastrous. Earthquake was felt in India, Iran, Bahrain, Afghanistan, Oman, Qatar and united Arab emirates. 2 women died due to this earthquake in Pakistan due to heart attack.
  • 33. 13th Deadliest Earthquake 2005 Kashmir Earthquake • • • • • • • Location: Muzafferabad, AJK Magnitude 7.8 Saturday, October 08, 2005 at 08:52:37 AM Distance: 105 km (65 miles) NE of ISLAMABAD, Pakistan 73,000 people were killed and more than 3.3 million made homeless. Economic down fall. Pak declared as failed state.
  • 34. Volcanoes of Pakistan: Tor Zawar • • The only known volcanic activity in Pakistan was in January 2010. A small fissure eruption in the Ziarat region of west-central Pakistan produced a small lava flow in an area with no previous volcanic activity. Wednesday, February 03, 2010 • Trachybasalt and basalti c-andesite in composition. Chandragup is a mud volcano located in Balochistan, Pakistan
  • 35. Malan Island is an offshore mud volcano located in the Arabian Sea, 3 kilometers off the coast of Balochistan, Pakistan. It rose out of the water overnight in March 1999. Jebel e Ghurab, is located in Balochistan, Pakistan. It is a mud volcano. Neza e Sultan, is located in Chagai District, Balochistan, Pakistan. Neza e Sultan is an extinct volcano and only the magma chamber remains and it looks like a spear.
  • 36. This was All from the Presentation …….. Thankyo u