1. Earthquake and Volcanoes This map shows only the known faults in Oregon. Faults that have moved most recently are shown in red.

5. I. Earthquakes A. Earthquake: the shaking and trembling that results from the movement of rock beneath the Earth’s surface. 1. Seismology – the study of Earthquakes 2. Seismologist – geologist that studies earthquakes 3. Stresses causing earthquakes a. Shearing b. Compression c. tension Seismologist

7. Questions 1.____________________________ is the study of earthquakes. 2.A ___________________________ is a person who studies earthquakes. 3.Stress at tectonic plate boundaries causes earthquakes. The three types of stress are: a._____________________________ b._____________________________ c._____________________________

8. Questions 1. Seismology is the study of earthquakes. 2.A seismologist is a person who studies earthquakes. 3.Stress at tectonic plate boundaries causes earthquakes. The three types of stress are: a. compression b. tension c. shearing

9. Earthquakes cont. 4. Detecting earthquakes a. Seismic waves – vibrations that travel through the Earth carrying the energy released during an earthquake / Earthquake waves. b. Seismograph – instrument that detects and measures seismic waves 1. Primary Waves – P waves –Push/pull waves (accordion style) –Travel fastest –Travel through solids, liquids and gases

11. Earthquakes cont. 2. Secondary Waves – S waves –Arrive after P waves –Waves vibrate or move side to side and up and down –Travels through solids only 3. Long or Surface Waves – L waves –Slowest moving –Originate on the surface at the epicenter –Rolling or side to side motion –Travels through solids only A highly simplified simulated recording of earthquake waves (a seismogram) can be seen to the left. Study this sample seismogram and be sure you can identify these parts: P-waves and the P-wave arrival time S-waves and the S-wave arrival time S-P interval (expressed in seconds) S-wave maximum amplitude (measured in mm)

12. The seismogram below shows the arrival times of an earthquake’s P -wave and S -wave recorded at a seismic station in Portland,Oregon.

13. Questions 1.________________________________ are vibrations that travel through the Earth. 2._____________________ waves (P-waves) have a ____________________________ motion. 3.S-waves, or __________________________ waves, arrive after the P- waves, and move in a __________________________________ motion. 4.Long or ______________________ waves (L-waves) originate on the surface and have a _________________________________ motion. 5.Fill in the chart by placing check marks in the appropriate boxes that show through which states of matter each type of wave can travel: solidliquidgas P-waves S-waves L-waves

14. Questions 1. Seismic waves are vibrations that travel through the Earth. 2. Primary waves (P-waves) have a push-pull motion. 3.S-waves, or secondary waves, arrive after the P-waves, and move in a side to side and up and down motion. 4.Long or surface waves (L-waves) originate on the surface and have a rolling or side to side motion. 5.Fill in the chart by placing check marks in the appropriate boxes that show through which states of matter each type of wave can travel: solidliquidgas P-wavesx x x S-wavesx L-waves x

15. Earthquakes cont. c. Focus – point beneath the surface where the earthquake begins. d. Epicenter – point on the surface where the earthquake is located. –Directly above the focus –Energy of the seismic wave is the greatest here –The types of rock and soil around the epicenter affect how much the ground shakes. –Most violent shaking occurs here

18. e. Earthquakes occur along fault lines at the edges of the tectonic plates.

19. Questions 1.The __________________ is the point beneath the surface of the earth where the earthquakes originate. 2.The __________________ is the point on the surface of the earth directly above the focus. 3.Earthquakes occur along _____________________ lines on the edges of ____________________ plates.

20. Questions 1.The focus is the point beneath the surface of the earth where the earthquakes originate. 2.The epicenter is the point on the surface of the earth directly above the focus. 3.Earthquakes occur along fault lines on the edges of tectonic plates.

21. Measuring Earthquakes a. Magnitude – is a measurement of earthquake strength based on seismic waves and movement along faults. b. Three ways of measuring earthquakes: 1.Richter Scale – a rating of the size of seismic waves as measured by a mechanical or electronic seismograph. Earthquakes cont.

23. –Provides accurate measurements for small, nearby earthquakes –Less reliable for distance or large quakes 2. Mercalli scale – rates earthquakes according to their intensity. –Not a precise measurement –Describes how the earthquake affects people, buildings and the land surface

24. Earthquakes cont. –Same quake can have different ratings because of different amounts of damage at different locations. 3. Moment Magnitude Scale – estimates the total energy released by an earthquake. –Rates all size earthquakes, near and far –Example: a magnitude 6 earthquake compared to a magnitude 5, releases 32 times as much energy as a 5 and nearly 1000 times as much as a 4 earthquake. The Richter scale measures the energy released in an earthquake by measuring the size of the seismic waves. The Mercalli scale measures the results of an earthquake, such as the shaking and damage that people actually feel and see.

26. Modified Mercalli Scale

27. Questions 1.What is magnitude? 2. What are the three ways of measuring earthquakes? a. b. c.

28. Questions 1.What is magnitude? A measurement of earthquake strength based on seismic waves and movement along faults. 2. What are the three ways of measuring earthquakes? a. The Richter Scale b. Mercalli Scale c. Moment Magnitude Scale

29. Earthquakes cont. B. Earthquake Hazards and Safety 1. How earthquakes cause damage – the severe shaking produced by seismic waves can cause damage near the epicenter or at great distances. a. Local soil conditions – the thick, loose soil shakes more violently than dense rock b. Liquefaction- occurs when an earthquake’s violent shaking turns loose, soft soil to mud which can sink buildings, or cause landslides

30. Earthquakes cont. c. Aftershocks – an earthquake that occurs after a larger earthquake in the same area d. Tsunamis – tidal wave e. Indirect damage from fire or flooding 2. Monitoring Faults – earthquakes are very unpredictable but certain P & S wave patterns can be monitored. a. seismograph readings

31. Thursday, January 04, 2007 at 08:30:11 UTC Earthquake Location Major Tectonic Boundaries: Subduction Zones -purple, Ridges -red and Transform Faults -green

32. DescriptionRichter MagnitudesEarthquake EffectsFrequency of Occurrence MicroLess than 2.0Micro earthquakes, not felt.About 8,000 per day Very minor2.0-2.9Generally not felt, but recorded.About 1,000 per day Minor3.0-3.9 Often felt, but rarely causes damage. 49,000 per year (est.) Light4.0-4.9 Noticeable shaking of indoor items, rattling noises. Significant damage unlikely. Much like a passing truck 6,200 per year (est.) Moderate5.0-5.9 Can cause major damage to poorly constructed buildings over small regions. At most slight damage to well-designed buildings. 800 per year Strong6.0-6.9 Can be destructive in areas up to about 100 miles across in populated areas. 120 per year Major7.0-7.9 Can cause serious damage over larger areas. 18 per year Great8.0-8.9 Can cause serious damage in areas several hundred miles across. 1 per year Rarely, great9.0 or greater Devastating in areas several thousand miles across. 1 per 20 years

33. The Richter Scale MagnitudeEffects Estimated Number Per Year less than 2.5 Usually not felt, but can be recorded by seismograph 900,000 2.5 to 5.4Often felt but only causes minor damage30,000 5.5 to 6.0Slight damage to structures500 6.1 to 6.9May cause much damage in populated areas100 7.0 to 7.9Major earthquake; serious damage20 8.0 or greater Great earthquake; can totally destroy communities near the epicenter One every 5-10 years

35. Earthquakes cont. b. satellite monitors c. laser-ranging devices d. creep meters – wire stretched across a fault to measure horizontal ground movement 3. Making buildings safer a. Location b. Construction methods – Materials used –Building codes

36. Earthquakes cont. 4. Safety a. Drills b. Take Precautions during and after quake c. Preparedness – earthquake kit

37. Questions 1.What are three things that can cause damage after an earthquake? a. b. c. 2.Two ways scientists can monitor earthquakes are: a. b. 3.What are two ways to make buildings safer in case of earthquakes? a. b. 4.What are two things people can do to be safer in case of earthquakes? a. b.

38. Questions 1.What are three things that can cause damage after an earthquake? a. Loose soil, liquefaction, aftershocks, tsunamis, fires, flooding b. c. 2.Two ways scientists can monitor earthquakes are: a. seismograph readings, satellite monitors, laser devices, creep meters b. 3.What are two ways to make buildings safer in case of earthquakes? a. location, materials used, building codes b. 4.What are two things people can do to be safer in case of earthquakes? a. safety drills, precautions during and after quake, earthquake kits b.

39. II. Volcanoes A. Volcano: a weak spot in the earth’s crust where molten material, or magma, comes to the surface as lava. 1. Volcanology – study of volcanoes 2. Volcanologist – geologist that studies volcanoes 3. Volcanoes and Plate Tectonics a. Most volcanoes occur along divergent plate boundaries such as the mid-ocean ridge, or in subduction zones around the edges of oceans. Mt. Etna, Sicily (2002-03)

44. Volcanoes cont. b. Magma – molten mixture of rock-forming substances, gases and water vapor from the mantle. Occurs underground. c. Lava – when the magma reaches the surface. d. Hot spot – an area where magma from deep within the mantle melts through the crust like a blow torch. e. Hot spots in the ocean floor create islands such as the Hawaiian Islands

46. Volcanoes cont. e. a volcano forms where magma breaks through the earth’s crust and lava flows to the surface Volcanic vent on the Big Island, Hawaii

47. Questions 1.A volcano is a _______________________________ in the Earth’s ________________ where ________________________ comes through. 2.The study of volcanoes is called ____________________________________________. 3.What is the difference between magma and lava? ______________________________________________________________ ______________________________________________________________ 4. ________________________ are areas where magma melts through the crust. This phenomenon created the __________________________________.

48. Questions 1.A volcano is a weak spot in the Earth’s crust where magma comes through. 2.The study of volcanoes is called volcanology 3.What is the difference between magma and lava? Magma is molten material below the earth’s surface; lava is molten material on top of earth’s surface. 4. Hot spots are areas where magma melts through the crust. This phenomenon created the Hawaiian Islands.

49. 4. Volcanic Activity a. Inside a Volcano Magma chamber – pocket of magma beneath the volcano Pipe – a long tube in the ground that connects the magma chamber to the surface, magma flows through this tube Vent – opening where molten rock and gas leave the volcano Volcanoes cont.

50. b. Lava flow – the area covered by lava as it pours out a vent. c. Crater – a bowl-shaped area that may form at the top of a volcano around the volcano’s central vent.

51. Questions 1.Diagram a volcano. Draw and label the following parts in the correct places: magma chamber, vent, and crater.

52. Questions 1.Diagram a volcano. Draw and label the following parts in the correct places: magma chamber, vent, and crater.

53. 5. Types of Volcanic Eruptions – the silica content of the magma influences how the volcano erupts. a. Quiet Eruption – magma flows easily. Volcanoes cont.

54. Gas dissolved in the magma bubbles out gently Runny lava “oozes” quietly from the vent Produces two kinds of lava 1. pahoehoe – slow-moving, hot lava; cooled surface looks like wrinkles, or coils of hardened rock. 2. aa – faster-moving, cooler lava; cooled surface forms jagged lava chunks. Ex. Mount Kilauea pahoehoe Aa lava (14 cm x 12 cm). Kilauea,

55. Most Dangerous U.S. Volcanoes, in Descending Order 1. Kìlauea, Hawaii 2. Mount St. Helens, Washington State 3. Mount Rainier, Washington State 4. Mount Hood, Oregon 5. Mount Shasta, California 6. South Sister, Oregon 7. Lassen Volcanic Center, California 8. Mauna Loa, Hawaii 9. Redoubt Volcano, Alaska 10. Crater Lake area, Oregon 11. Mount Baker, Washington State 12. Glacier Peak, Washington State 13. Makushin Volcano, Alaska 14. Akutan Island, Alaska 15. Mount Spurr, Alaska 16. Long Valley caldera, California 17. Newberry Crater, Oregon 18. Augustine Island, Alaska Only three of the most dangerous U.S. volcanoes are sufficiently monitored, according to the report: Kìlauea in Hawaii, Mount St. Helens in Washington State, and the Long Valley caldera in California.

56. Volcanoes cont. b. Explosive Eruptions – magma does not flow but is blown out the volcano. Magma is thick and sticky building up in the volcano’s pipe, plugging it Trapped gases build up pressure until they explode The explosion breaks the lava into fragments that cool quickly in different sizes. 1. volcanic ash 2. cinders 3. volcanic bomb

57. Volcanoes cont. c. Pyroclastic Flow – occurs when an explosive eruption hurls out pyroclastic materials: ash, cinders, bombs and gases. Example – Mount St. Helens 6. Stages of a Volcano a. Active – a volcano that is erupting or has shown signs that it may erupt in the near future. Ex. Mt. St. Helens b. Dormant – a “sleeping” volcano, may erupt in the future. Ex. Mt. Hood Hualalai volcano, on the west side of the island, is also considered to be active. Its last eruption occurred in 1802.

58. c. Extinct- a dead volcano, unlikely to erupt again. Ex. Crater Lake Volcanoes cont.

59. 7. Other Types of Volcanic Activity a. hot spring – forms where underground water heated by a nearby body of magma rises and collects in a natural pool. b. Geothermal energy – energy source produced by water heated in volcanic areas and used for electricity. Mono Hot Springs Yellowstone National Park

60. Questions 1.The two types of volcanic eruptions are ______________________ and ______________________. 2.Pyroclastic flow consists of __________________, ____________________,__________________________, and ____________________. 3.Please complete the following chart: 4. What are two other types of volcanic activity? a. b. Volcano StageDescription May erupt in the future. Is unlikely to ever erupt again. Is erupting or may erupt soon.

61. Questions 1.The two types of volcanic eruptions are quiet and explosive. 2.Pyroclastic flow consists of ash, cinder, volcanic bombs, and toxic gases. 3.Please complete the following chart: 4. What are two other types of volcanic activity? a. hot springs b. geothermal energy Volcano StageDescription dormantMay erupt in the future. extinctIs unlikely to ever erupt again. activeIs erupting or may erupt soon.

62. Volcanoes cont. B. Volcanic Landforms 1. Shield Volcanoes – thin layers of lava pour out a vent and harden on top of previous layers. –Quiet eruptions –Wide, gently sloping mountain –Ex. – Hawaiian Islands 2. Cinder Cone Volcanoes – thick and stiff lava produce pyroclastic material: ash, cinder and bombs which pile up around the vent. Cinder cone Shield cone shield cinder Shield

63. Volcanoes cont. –Explosive eruptions –Steep, cone-shaped –Ex. Mt. Paricutin in Mexico C. Composite Volcanoes -lava flows alternate with explosive eruptions of pyroclastic material: ash, cinder and bombs. –Quiet and Explosive eruptions –Tall, cone-shaped –Layers of alternate ash and lava –Ex. Mt. St. Helens, Mt. Fuji Mount St. Helens in Washington State is an active composite volcano, towering in a conelike shape more than 8,000 feet (2,400 meters) above sea level. USGS/Cascades Volcano Observatory

64. Quintessentially Japan... Mt Fuji in the spring. Cherry season in Japan is a Barbara Cartland fantasy of pink flowers and purple prose. Picture: Brian Johnston

65. Background: Table Rock is a pint sized and remarkably symmetrical extinct volcanic cone, with a summit elevation of 5621’. It stands roughly 1000’ higher than the surrounding desert in a setting isolated from any nearby hills or peaks, which results in a unique and spectacular appearance. I t’s classic and distinctive shape can be seen for many miles in any direction. This structure appears to be a classic volcanic cone, but is actually a unique ‘maar’ cone created by the interaction between groundwater and magma. Table Rock

66. Volcanoes cont. 4. Lava Plateaus – high level areas formed by layers of lava. 5. Caldera – the hole left by the collapse of a volcanic mountain. Example Crater Lake caldera Volcanic neck That's a volcanic neck in the center, with a waterfall

67. Question 1.List and describe the three types of volcanoes: a. b. c. 2.________________________ are high, level areas formed by layers of lava. A caldera is formed by the ___________________________ of a ___________________________ mountain.

68. Question 1.List and describe the three types of volcanoes: a. Shield: made from thin layers of lava that build up b. Cinder Cone: made from piled up pyroclastic materials c. Composite: lava flows alternate with layers of pyroclastic materials 2. Lava plateaus are high, level areas formed by layers of lava. A caldera is formed by the collapse of a volcanic mountain.

69. Volcanoes cont. C. Landforms from Magma 1. Volcanic Neck – formed when magma hardens in a volcano’s pipe 2. Dike – magma forcing its way across underground rock layers and hardening Shiprock, in New Mexico, also a volcanic neck. Once again, the remainder of the volcano has eroded away, leaving only the relatively hard rock that cooled within the conduits feeding lava to the surface. In addition to the vertical pipe at the center, a series of dikes may be seen radiating away from the center. These formed when lava entered fractures which formed in the sides of the volcano Volcanic Dike along Ross Maxwell Scenic Drive

70. Volcanoes cont. 3. Sill – magma squeezes between rock layers and hardens 4. Batholith – is a mass of rock formed when a large body of magma cools inside the crust Below is a volcanic sill near Edinburgh, Scotland. Like a dike, a sill forms when magma fills fracture in the rock, then cools in place. A sill is largely horizontal, however, so it seems the magma spreading out between the layers of sedimentary rock. batholith

71. Volcanoes cont. 5. Dome Mountains – formed when rising magma is blocked by horizontal layers of rock, forcing the layers of rock to bend upward into a dome shape. Eventually the rock above the dome wears away leaving the dome mountain exposed.