Geology 104 Exam 2

Question Answer
Describe Hurricane Katrina August 2005. 80% of New Orleans was underwater.
How many people died in Katrina? 1,836 people
What size was the Storm Surge in Katrina? 3-6 meters
Why did Katrina cause so much severity? There was a sea level rise in the last 100 years due to Global Warming, and the geographic location was very vulnerable to flooding
What is the annual life loss and property damage of Natural Disasters? 150,000 people and 50 billion dollars in property damage
There is usually ? life loss in a developing country than in an developed country More
There is usually ? property damage in a developed country than a developing country More
Why do Natural Processes become hazards? They become hazardous when people live and work in places they occur, and when there is land-use changes (deforestation or urbanization)
Intensity of a natural hazard in terms of the amount of energy released Magnitude
Reoccurrence interval of a disastrous event Frequency
There is usually a ? relation between magnitude and frequency Inverse
Magnitude and frequency are controlled by ? factors, whereas Impact Risk is controlled by ? Natural Factors, both human and natural factors
Low magnitude and high frequency natural disasters are… Not always destructive
High magnitude and low frequency natural disasters are… Destructive
What are the benefits of hazards? Creates new land, supplies nutrients to soil, flushes away pollutants and changes landscapes
Consist of formed groundwater barriers, producing natural subsurface dams and water resources Fault Gouge
Disastrous situations requiring long processes to recovery from grave damages Catastrophe
What catastrophe causes the most deaths per year? Floods
Hazards are ? events Repetitive
In ?, the certainty of the event is given as the percent chance of happening Forecast
Tries to figure out the when, where, type and size of certain natural hazardous events Prediction
When does a warning happen? After the hazardous event has been predicted or forecast has been made
What is the risk impact to human life? Potential loss of life and injury
What is the risk impact to property? Damage or destruction
What is the risk impact to society? Services and function of society
Asia suffered the greatest losses from 1985 to 1997, with ? percent of the total deaths and ? percent of economic losses 77% of deaths and 45% of economic losses
Violent ground-shaking phenomenon caused by the sudden release of strain energy stored in rocks. One of the most catastrophic and devastating hazards Earthquake
Where are most earthquakes concentrated? Along plate boundaries
How many earthquakes are there annually? 1 million
The point at depth where the rocks ruptured to produce the earthquake Focus
Location on the surface of earth above the focus Epicenter
Measure of the Strain Energy released by earthquake. Estimated by examining records from seismographs. Gives most detail and is applicable over a wider range of ground motions Moment Magnitude Scale
Describes the energy released by an earthquake. Based on amplitude/size of the largest seismic wave produced by the earthquake Richter Magnitude Scale
Qualitative measurement of damages and ground movements. 12 divisions. Based on ground observations instead of measurements Modified Mercalli Scale
What kind of earthquakes do divergent plate boundaries have? Shallow
What kind of earthquakes do transform plate boundaries have? Shallow to Intermediate
What kind of earthquakes do convergent plate boundaries have? Shallow, Intermediate, and Deep
Earthquakes that concentrated along plate boundaries. Typically shallow and common Interplate Earthquakes
Type of earthquake that appears within the plate away from the boundaries Intraplate Earthquakes
Where are major places that Intraplate Earthquakes appear? Along the New Madrid Seismic Zone and in Charleston, SC
What are the 4 types of faults? Normal, Reverse, Thrust, and Strike-Ship
Long term rate of movement typically recorded as millimeters per year Slip Rate
Compressional Waves that travel fastest through all physical states of media P Waves
Sheer Waves that travel slower than P Waves but faster than Surface Waves. Only can go through solid materials S Waves
Waves that travel along the Earth's Surface. Travels slowest but causes the most damage Surface Waves/R Waves
Device that records seismic waves Seismograph
The record of an earthquake is called ? Seismogram
The idea that the intensity of ground shaking is more severe in unconsolidated materials Material Amplification
The idea that the intensity of seismic shaking increases in the direction of the fault rupture Directivity
When the propagation of the rupture is faster than the velocity of shear waves produced by the rupture (similar to a sonic boom). Produces shock waves that result in great damages Supershear
Model where the fault-valve mechanism hypothesizes that fluid pressure rises until failure occurs, thus triggering an earthquake Dilatancy Diffusion Model
What is the warning time for an earthquake? Usually only 1 minute
Japanese words for "large harbor waves", produced by the sudden vertical displacement of ocean water Tsunami
What can trigger tsunamis? Any rapid uplift or subsidence of the seafloor, such as a submarine earthqake, landslide, volcanism, or impacts of asteroids
Formed from asteroid impact, a wave about 100 times higher than the largest tsunami produced by an earthquake Mega-Tsunami
What size earthquake does it need to be to generate a tsunami? M 7.5 or greater
Type of tsunami that travels across the deep ocean at a high speed for thousands of kilometers to strike remote shorelines with very little loss of energy Distant Tsunami
Type of tsunami that heads in the opposite direction towards nearby land and arrives quickly following an earthquake Local Tsunami
When the initial wave is split, both local and distant tsunamis have a wave heigh about ? that of the original dome of water One half
What regions are at risk of tsunamis? All ocean and some lake shorelines, coasts that are close to a major subduction zone
What are the primary effects of a tsunami? Damages to landscapes and human structures
What are the secondary effects of a tsunami? Fire in urban areas, polluted water supplies, damaged water treatment systems, outbreak of disease
What are the 3 components of Tsunami Warning Systems? 1. Seismographs 2. Automated Tidal Gauges 3. Network of sensors connected to buoys
Product of the probability of the event occurring and the consequences Risk
How many active volcanoes are their on earth, and how many erupt per year? 1500 active, 50 eruptions per year
Where are most volcanoes found? Along major plate boundaries
Volcanic activity, directly related to plate tectonics Volcanism
Part of the Pacific where 2/3rd of the active volcanoes are located Ring of Fire
Where are the volcanoes located in the US? Alaska, Hawaii, and the Cascades
Where does magma come from? The Asthenosphere
Occurs when the overlying pressure exerted on hot rocks within the asthenosphere is decreased Decompression Melting
Liquid's resistance to flow. Determine by silica content and lava temp Viscosity
What is an example of a rock with a very high silica content? Quartz Sandstone
A low silica content is ?% and a high silica content is ?% Low – 50%High – 100%
Type of volcano, built from Basaltic lava flow. Very gentle slope near top but increases on flanks. Formed above hot spots Shield Volcano
Type of volcano, known for beautiful cone shape. Has magma with intermediate sigma content, distinguished by a mixture of explosive activity and lava flows Composite Volcanoes
Type of volcano, characterized by viscous magma with a relatively high silica content. Produces the rock rhyolite Volcanic Domes
Type of volcano, relatively small. Formed from tephra, ash, and volcanic bombs, Extremely explosive and violent, usually found inland of subduction zones Cinder Cones
Collapsed craters that typically form explosive eruptions Caldera
How does lava flow? From the vent of crater or along the line of a fissure
What is the most common and abundant lava type? Basaltic Lava Low
Type of lava, less viscous, higher temp with a smooth ropy surface texture Pahoehoe Lava
Type of lava, more viscous and slow moving, lower temp with a blocky surface texture Aa Lava
Volcanic eruption in 1991, killed 350 people and destroyed a military base. Affected the global climate for a year by making it colder Mt. Pinatubo
Volcanic eruption in 1980 after a 120 year dormancy. Set of by an earthquake. Ash spread over 3 states. Killed 54 people Mt. St Helens
What is usually used to forecast volcanic activity? Studying the amount of volcanic gas and emission, topographic monitoring, and remote sensing

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