Details Title: Exam 2 Description: Natural Hazards, Volcanos Total Flash Cards: 77 Created: 03/15/2009 18:48:47		New Users: To study from this flashcard set, or to create your own your own study flash cards, REGISTER HERE. Existing Users: CLICK HERE. Additional Geology Flashcards
Cards in this set: Term which of the following is not a natural hazard? Definition volcano, earthquake, hurricane, tsunami, mudslide Term How does a catastrophe differ from a disaster? Definition A catastrophe requires a long recovery time while a natural disaster is not one unless there is population density, land use, magnitude & frequency Term Why is history important in understanding natural hazards? Definition It helps predict the the next eruption or disaster by following a pattern. Term Why are precursor events important? Definition help with evacuation/saving lives Term To what does the concept of acceptable risk refer? Definition risk society willing to endure Term why does population increase affect the number of catastrophic events? Definition thicker the population density and land use among other things increases the severity of what might be considered a disaster Term Which of the following natural hazards is not likely to occur in Michigan? Definition tsunami, hurricane, earthquake, volcano, tornado Term How does earthquake magnitude differ from intensity? Definition magnitude refers to the quantitative and the intensity refers to the qualitative. Term The 1811-1812 New Madrid earthquakes were different from most California earthquakes because... Definition It was an intraplate earthquake rather than an interplate EQ/much stronger than interplate/ rocks stronger in Eastern US Term A strike-slip fault has what type of motion? Definition right lateral vs. left lateral Term Surface waves are produced by... Definition seismic activity, volcano? earthquake? Term During the strain accumulation phase of the earthquake cycle... Definition pressure builds up Term Why might the emission of radon gas be useful in predicting earthquakes? Definition radon gas is emitted from rocks electrical currents while the pressure builds before the actual earthquake Term Which of the following is not a likely effect of an earthquake? Definition shaking, ground rupture, liquefaction (saturated sediment becomes liquid), landslides, fires, diseases, tsunamis, land topography Term Why is ravine erosion a problem at Grand Valley State University? Definition Because the foundations of the buildings could be affected Term Viscosity of magma is controlled by what? Definition temperature Term Why do composite volcanoes consist of alternating lava and pyroclastic layers? Definition The lava flows then the ash falls on top of that layer and then is covered by more lave and so on Term The shape of shield volcanoes is a function of Definition many lava flows, low viscosity Term Mid-ocean ridge volcanism produces what type of volcanic rock? Definition basalt Term Composite cones typically are associated with what type of plate tectonic feature? Definition subduction Term What is the principal difference between craters and calderas? Definition crater is a depression at top of volcano only a few km's a caldera is 20 or more km's Term Why were the citizens of Heimaey, Iceland, successful in stopping the lava flow that threatened their harbor? Definition hydraulic chilling Term What is one reason that ash fall is such a significant hazard? Definition can destroy crops and land use for years Term Hundreds of residents near a dormant volcano at Lake Nyos died when Definition CO2 released into the air Term The number of fatalities from the Mt. Pinatubo eruption was relatively low because Definition much effort made to evacuate when volcanic activity warned officials Term Seismic activity serves as a tool of volcanic forecasting because Definition molten lava rising to the crust creates earthquakes through disruption of the rocks before the actual eruption Term Why is the geologic history of a volcano important in hazard prediction? Definition because volcano's erupt every X years give or take a couple thousand years Term Why is topographic monitoring sometimes useful in forecasting a volcanic eruption? Definition The seismic activity created by volcanic activity can sometimes cause the topography to shift Term The portion of rainfall that flows off the land and directly into a river is called... Definition runoff Term What is river base level? Definition the lowest point which a river can erode to...usually being sea level Term The suspended load of most rivers consists mostly of... Definition sediment carried above streambed Term If a stream channel is of constant width and depth, how must increased discharge be accommodated? Definition bigger floodplain Term The total load of sediment that a river carries in a given period of time is called Definition Total Load/Discharge Rate? Term Which type of seismic wave has the highest amplitude? Definition Surface Waves (R-Waves) Term Material Amplification refers to... Definition seismic shaking amplified through soft sediments such as clay and silt Term WAVE FORMULA Definition Velocity = Wavelength * Frequency Term A caldera eruption would likely be _________ times greater than the eruption of Mount Saint Helens in 1980. Definition 1,000 times more Term Which of the following is not considered a primary effect of a volcanic eruption? Definition Term Which of the following is not considered a primary effect of a volcanic eruption? Definition Primary Effects are effects that are a direct result of the volcano Term Where is the world’s largest active landslide? Definition Hawaii Term The eruption of Mount Saint Helens began with a(n) Definition a horizontal blast blowing off a chunk of the side of teh volcano Term Which of the following is the best solution to the ravine problem? Definition riprap/helicoptering in rocks Term Which of the following rock types would be considered mafic? Definition basalt Term What was the magnitude of the earthquake that caused the 2004 Indonesian Tsunami? Definition 9.0 Term What caused the majority of deaths in the case history of Nevado del Ruiz? Definition hazard maps were circulated but not explained correctly Term The difference between an upstream and a downstream flood is . . . ? Definition upstream flood is caused by intense rainfall in the upper drainage basic while downstream is caused because of longer storming that saturates the soil Term What is the difference between a reactive and anticipatory response? Definition anticipatory response is a result of information obtained prior to an event while reactive response is a response to an event already happening Term Why might global climate change impact the magnitude and frequency of hazardous events? Definition because the temperature and pressure of the global climate greatly affects the magnitude and frequency of hazardous events Term Why might global warming increase the magnitude and/or frequency of weather-related hazards? Definition An increase in the average temp. of the global climate would lead to higher frequency Term Mercalli intensity values assigned to locations how? Definition based on observers Term Why might global warming increase the magnitude and/or frequency of weather-related hazards? Definition An increase in the average temp. of the global climate would lead to higher frequency Term How can injection of liquid wastes cause earthquakes? Definition creates stress by altering the underlying rocks Term Why have 20th Century earthquakes in Turkey suggested that some earthquakes beget subsequent earthquakes? Definition Term An active fault is defined as a fault that.. Definition Still displays seismic activity Term Why did the 1976 Tanshan earthquake in China deal a blow to the Chinese earthquake prediction program? Definition Term The deadly 1985 eruption of Nevado del Ruiz is an example of inaccurate prediction. Definition False Term Volcanic eruptions are one of the few natural hazards that have no benefit to humans. Definition False Term The focus is the point at depth where the rocks ruptured to produce the earthquake. Definition False Term An earthquake with a deep focus is more destructive than an earthquake with a shallow focus. Definition False Term Mudslides may be caused by plate tectonics or atmospheric disturbance. Definition True Term Viscosity is a primary control on the nature of volcanic activity. Definition True Term Hot lava typically flows faster than cold lava of similar composition Definition True Term A shield volcano is typically andesitic in composition. Definition True Term Bubbles stay preserved the longest in the lava with the lowest viscosity. Definition False Term Lava with high solid content flows faster than lava with low solid content. Definition False Term Lava flows are the most dangerous of the primary volcanic hazards. Definition False Term The 1980 eruption of Mt. St. Helens produced large lava flows that filled the nearby river valleys. Definition True Term Base Level of a stream is typically sea level Definition True Term There was no secondary prevention for flooding in the New Orleans, Hurricane Katrina case history. Definition True Term The November 2002 earthquake that occurred in Alaska was classified as a disaster due to a rupture of the oil pipeline. Definition False Term Levees constructed on the Mississippi River provided a false sense of security to landowners along its banks. Definition False Term A catastrophe is an event that requires a long recovery period. Definition True Term Most natural hazards are non-repetitive events. Definition False Term The epicenter of an earthquake is the point of rupture along the fault. Definition True Term Depth of focus is an important factor in determining the intensity. Definition True Term Most large earthquakes in the U.S. are interplate earthquakes. Definition False Term The magnitude of an earthquake is a function of its location. Definition True