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A) Precipitation of Minerals from Evaporating Seawater B

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A) Precipitation of Minerals from Evaporating Seawater B 1. Which process could lead directly to the formation of pumice rock? A) precipitation of minerals from evaporating seawater B) metamorphism of unmelted rock material C) deposition of quartz sand D) explosive eruption of lava from a volcano Base your answers to questions 2 through 4 on the map below. The black triangle represents Mt. Hekla, a volcano in Iceland. The isolines represent the thickness of ash, in centimeters, that settled on Earth's surface after a volcanic eruption of Mt. Hekla on March 29, 1947. Point X is a location on the surface of the ash. 2. At the time of the eruption, the wind direction was primarily from the A) east B) west C) north D) south 3. How many centimeters thick was the ash beneath point X? A) 0 B) 15 C) 20 D) 25 4. In addition to the ash, solid rock formed on Mt. Hekla from the lava extruded during this eruption. This rock is most likely A) light-colored metamorphic B) dark-colored metamorphic C) fine-grained igneous D) coarse-grained igneous 5. Base your answer to the following question on the map below, which shows an area of the northwestern United States affected by a major volcanic eruption at Crater Lake during the Holocene Epoch. The pattern of distribution of the ash from the volcano was most likely caused by the direction of the A) magnetic field B) force of the volcanic eruption C) flow of surface water D) atmospheric air movements 6. Base your answer to the following question on the cross section and map of a portion of Earth's crust shown below. The cross section and map show parts of the Pacific, Juan de Fuca, and North American tectonic plates, and Earth's interior. Letters A through F represent locations in the rock. The arrows indicate the general direction of plate movement relative to one another. The Mount St. Helens volcano is composed mostly of andesite rock. Therefore, the most common minerals at this location are A) potassium feldspar and quartz B) pyroxene and olivine C) plagioclase feldspar and hornblende D) biotite mica and quartz 7. An Earth science class is preparing a booklet on emergency preparedness. State one safety measure that should be taken to minimize danger from each of the following threats. a Thunderstorm b Tornado c Volcanic eruption Base your answers to questions 8 through 13 on the reading passage and maps below. The enlarged map shows the location of volcanoes in Colombia, South America. Fire and Ice — and Sluggish Magma On the night of November 13, 1985, Nevado del Ruiz, a 16,200-foot (4,938 meter) snowcapped volcano in northwestern Colombia, erupted. Snow melted, sending a wall of mud and water raging through towns as far as 50 kilometers away, and killing 25,000 people. Long before disaster struck, Nevado del Ruiz was marked as a trouble spot. Like Mexico City, where an earthquake killed at least 7,000 people in October 1985, Nevado del Ruiz is located along the Ring of Fire. This ring of islands and the coastal lands along the edge of the Pacific Ocean are prone to volcanic eruptions and crustal movements. The ring gets its turbulent characteristics from the motion of the tectonic plates under it. The perimeter of the Pacific, unlike that of the Atlantic, is located above active tectonic plates. Nevado del Ruiz happens to be located near the junction of four plate boundaries. In this area an enormous amount of heat is created, which melts the rock 100 to 200 kilometers below Earth's surface and creates magma. Nevado del Ruiz hadn't had a major eruption for 400 years before this tragedy. The reason: sluggish magma. Unlike the runny, mafic magma that makes up the lava flows of oceanic volcanoes such as those in Hawaii, the magma at this type of subduction plate boundary tends to be sticky and slow moving, forming the rock andesite when it cools. This andesitic magma tends to plug up the opening of the volcano. It sits in a magma chamber underground with pressure continually building up. Suddenly, tiny cracks develop in Earth's crust, causing the pressure to drop. This causes the steam and other gases dissolved in the magma to violently expand, blowing the magma plug free. Huge amounts of ash and debris are sent flying, creating what is called an explosive eruption. Oddly enough, the actual eruption of Nevado del Ruiz didn't cause most of the destruction. It was caused not by lava but by the towering walls of sliding mud created when large chunks of hot ash and pumice mixed with melted snow. 8. What are the names of the four tectonic plates located near the Nevado del Ruiz volcano? 9. What caused most of the destruction associated with the eruption of Nevado del Ruiz? 10. What caused the magma to expand, blowing the magma plug free? 11. Vesicular texture is very common in igneous rocks formed during andesitic eruptions. Explain how this texture is formed. 12. Why are eruptions of Nevado del Ruiz generally more explosive than most Hawaiian volcanic eruptions? 13. Describe one emergency preparation that may reduce the loss of life from a future eruption of the Nevado del Ruiz volcano. Base your answers to questions 14 through 18 on the passage and the map below. The passage describes the New Madrid fault system. The numbers on the map show the predicted relative damage at various locations if a large earthquake occurs along the New Madrid fault system. The higher the number, the greater the relative damage. The New Madrid Fault System The greatest earthquake risk area east of the Rocky Mountains is along the New Madrid fault system. The New Madrid fault system consists of a series of faults along a weak zone in the continental crust in the midwestern United States. Earthquakes occur in the Midwest less often than in California, but when they do happen, the damage is spread over a wider area due to the underlying bedrock. In 1811 and 1812, the New Madrid fault system experienced three major earthquakes. Large land areas sank, new lakes formed, the course of the Mississippi River changed, and 150,000 acres of forests were destroyed. 14. On the map above, draw the 4, 6, and 8 isolines indicating relative damage. 15. Using the predicted damage numbers, place an X on the map to indicate where the New Madrid fault system most likely exists. 16. The distance between the New Madrid fault system and Albany, New York, is 1800 kilometers. What was the time difference between the arrival of the first P-wave and the arrival of the first S-wave at Albany when the 1812 earthquake occurred? 17. State one reason why earthquakes occur more frequently on the western coast of the United States than in the New Madrid region. 18. An emergency management specialist near the New Madrid region is developing a plan that would help save lives and prevent property damage in the event of an earthquake. Describe two actions that should be included in the plan. 19. Base your answer to the following question on the cross section below, which shows the paths of seismic waves traveling from an earthquake epicenter through the different layers of Earth's interior. No P-waves or S-waves are received in the shadow zone because A) P-waves are absorbed and S-waves are refracted by Earth's outer core B) P-waves are refracted and S-waves are absorbed by Earth's outer core C) both the P-waves and S-waves are refracted by Earth's outer core D) both the P-waves and S-waves are absorbed by Earth's outer core 20. Earthquake S-waves do not travel through the 22. A seismograph station recorded the arrival of the Earth's first P-wave at 7:32 p.m. from an earthquake that occurred 4000 kilometers away. What time was it at A) crust B) moho the station when the earthquake occurred? C) mantle D) core A) 7:20 p.m. B) 7:25 p.m. 21. A P-wave takes 8 minutes and 20 seconds to travel from the epicenter of an earthquake to a seismic C) 7:32 p.m. D) 7:39 p.m. station. Approximately how long will an S-wave take to travel from the epicenter of the same earthquake to this seismic station? A) 6 mm 40 sec B) 9 mm 40 sec C) 15 mm 00 sec D) 19 mm 00 sec 23. The seismogram below shows the arrival times of P- 27. A huge undersea earthquake off the Alaskan and S-waves from a single earthquake. How far from coastline could produce a the earthquake epicenter was the station that A) tsunami B) cyclone recorded this seismogram? C) hurricane D) thunderstorm A) 1.5 × 103 km B) 2.5 × 103 km C) 3.0 × 103 km D) 4.0 ×103 km 24. Which graph best represents the relationship between volcanic activity and earthquake activity in an area? A) B) C) D) 25. The difference in arrival times for P- and S-waves from an earthquake is 5.0 minutes. How far away is the epicenter of the earthquake? A) 1.3 × 103 km B) 2.6 × 103 km C) 3.5 × 103 km D) 8.1 × 103 km 26. When the seafloor moves as a result of an underwater earthquake and a large tsunami develops, what will most likely occur? A) Deep-ocean sediments will be transported over great distances.
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