Exam

List and briefly explain three important steps/actions in natural hazard mitigation discussed in the lecture.

1. Evaluate the Risk by collecting historical and new geologic information about the area and the hazard. 2. Study the hazard area and make plans to help reduce death and destruction. For example making evacuation plans. 3. Have a recovery plan for how to help people after the disaster and those displaced. Ideas for how and when people should be allowed to return to the hazard area. Your step 2 and 3 go together. step 3 is an assessment after the event. What worked and didn't.....

The Mercalli scale measures earthquake damage and effects on humans and it has _____ total classes.

12

The current world population at the beginning of 2022 is estimated to be ____.

7.9 billion

A _____ travels fastest and moves in a push-pull fashion of alternating pulses of compression (push) and extension (pull).

P-waves or primary waves are also called compresional waves and propogate forward with a push and pull movement parallel to the direction of the wave movement.

The growth rate of world population is about ____ per year, and has been _____ since the late1980s.

Population growth was around 2% by 1960, today it has declined to just above 1%. Overall population growth is declining slightly. or 1%

________ are the down-dropped areas in the middle of spreading-center domes that are being pulled apart.

Rift Valley

The large left step in the San Andreas Fault in the Los Angeles area causes compressive ruptures along east-west-oriented ________ faults as in the 1971 San Fernando and 1994 Northridge events.

Thrust

The deepest areas of the ocean basins called deep ocean trenches correlate to ______ plate boundaries.

convergent Deep ocean trenches form at convergent plate boundaries becasue subduction of an ocean plate causes the formation of a deep linear basin parallel to the boundary.

A "rift valley" forms at a ___ plate boundary.

divergent

The point on Earth's surface directly above the point where the fault first ruptures is called the ________.

epicenter

The phenomena of "resonance" describes what happens when the period of the passing seismic wave is _____ the period of the building the seismic waves are shaking. This resonance can then cause ____ the shaking of the building.

equal to, an increase in (or amplification of)

The rapid increase in human population during the past several centuries is an example of ________ growth.

exponential

As human population increases within a nation, the annual death toll from natural disasters has a tendency to ________.

increase because of increased urbanization of areas that have potential natural hazards present and are likely to experience a natural disaster in the future

Earthquake-induced ground motions cause buildings to sway at certain periods. In general, the taller the structure, the ________ the period.

longer (slower)

which of the following states has the highest earthquake risk?

Arkansas

What type of fault is shown in the photograph of the street and sidewalk shown below side walk

right-lateral iI standing on the black closest to the bottom of the image. The earth is horizonally displaced not vertically. If you look across the fault line, the block of earth has moved to the right

The seismic-gap method of earthquake forecasting works by identifying ________.

segments along a fault that not moved for the longest amount of time

Organic material in sediment layers found in California sag ponds along the San Andreas fault can be dated by measuring the amount of radioactive ________ present.

Carbon

Quiz 4 When several earthquakes occur along in the same general area of a fault over the course of a few months or years, the event is referred to as an earthquake . (Choose one: batch, bundle, cluster, clutch, episode, sequence, series)

Cluster

This type of seismic body wave can travel through solids, but does not travel through liquids or gasses.

shear wave

The mesosphere of the Earth is a _____ and acts _____ when put under stress.

solid, like a plastic The mesosphere is solid with a density higher than the lithosphere, but unlike the lithosphere which is brittle the mesosphere acts like a plastice when put under stress, similar to what happens in a glacier made of soild ice crystals.

The concept of supporting all of the Earth's human population without depleting resources over the long term would be classified as _______ within the field of environmental geology.

sustainability

The frequency of a seismic wave is ________.

the number of seismic waves passing a given point per second Frequency in all wave forms is number of wave crests per second (cycles per second or Hz). The inverse of frequency is the wave period (time between wave crests).

Quiz 3 A normal fault can be recognized in a cross-sectional profile because in this type of fault, the hanging wall moves ________ relative to the footwall.

Down

A triple junction is the point where ________.

three tectonic plates touch

Which image below best illustrates the hypothesized pattern of mantle convection under an ocean spreading ridge

top going out <- -> bottom <_. _> > < d" is correct because it shows upwelling (upward flow) below the spreading center in the ocean ridge. Flow then moves away from the ridge, then it sinks some distance from the ridge and completes the convection cycle in the lower mesosphere (or mantle).

which of the folowing best displays a country moving from very early to after in the demographic transition theory, the population would go from ________ .

very high death rates and very high birthrates to low death rates and low birthrates.

Deep earthquakes will occur near ________? Select all the apply

volcanic mountains trenches island arcs Deep focus earthquakes occur at convergent boundaries (trenches, island arc, and Volcanic Mountains)

Liquefaction occurs when seismic waves cause ________.

water to be injected into sediment causing the grains to lose cohesion and behave like a fluid

The Dead Sea and the Sea of Galilee ________.

are pull-apart basins and the result of strike-slip motion

A tall office building built on a foundation designed to slide or roll with an earthquake is an example of using ________ to reduce earthquake-induced damage.

base isolation

When the part of California west of the San Andreas Fault detaches from rest of California and moves north with the Pacific Place, it will plow into Alaska and _____.

become part of Alaska's southern margin The west side of the San Andreas Fault is on continental crust which is attached to the Pacific Plate. That area of the Pacific Plate is moving roughly to the north toward Alaska. The ocean crust located between this section of CA and Alaska will subduct at the Aleutian treach but once the section of continental crust which is less dense arrives it will actually pile up against Southern Alaska creating a continent-continent collision boundary.

Which of the following is not a divergent margin?

Aleutian Island Arc Aleutian Islands formed due to the subduction of the Pacific Plate beneath a section of the North American plate to the north.

The "sea-floor spreading hypothesis" was proposed by ______ in the late 1950s early 1960s

Harry Hess and Robert Dietz Both Harry Hess and Robert Dietz are given credit for coming up with the hypothesis of sea-floor spreading becasue they came up with nearly the idea independently in the late 1950s. Sometimes Harry Hess is given sole credit but this has been shown to be incorrect by historians of science. Both published at nearly the same time so both are given credit for the hypothesis.

Which one of the following energy sources provides most (>50%) of Earth's internal heat energy (or geothermal heat)? This heat energy along with gravity drives volcanic and earthquake events.

Heat produced from radioactive decay of elements; this heat is produced by elements present in Earth's mantle and crust

Which one of the following pieces of evidence was NOT proposed by Alfred Wegener in his book The Origins of Continents and Oceans?

Ocean ridges are found in all the world's ocean basins, and sea floor sedment is not found on mid-ocean ridges where a central valley is present. Wegener in early 1900's had little data about the oceans and he wasn't aware of the presence of ocean ridges or the distribution of sediment on the ocean floor. These observations becasue more well know after WWII when sonar and seismology began to find out these things.

Which of the following statements below most precisely defines a scientific theory?

Scientific theories are a set of well-tested hypotheses that have been widely accepted by scientists working in the field. Scientific theories are a set of well-tested hypotheses that have been widely accepted by scientists working in the field. The are made up of many well-tested hypotheses and scientific laws so are bigger and more complex than a single hypothesis. They well accepted in the field, but they are always questioned and tested as more information becomes available. Please listen to the module on plate tectonic theory where I make these points.

quiz 1 By definition, the "growth rate" of world population is equal to ________

The growth rate of world population = birth rate (fertility) - death rate (mortality). Since the question asked about "world population growth" we don't have to take into account net migration into and out of the Earth, as we would need to do if we were estimating the grow rate of a single nation or locality.

quiz 2 If a rock sample contains radioactive material with a half life of 4,670 years. The rock sample contains 75% parent material and 25% daughter material. Determine how many half-lives have occurred and how old is the rock sample?

The problem states that 75% of the sample is the parent material (unstable radioactive material). Find the 75% parent material on the vertical axis. Draw a horizontal line to the decay curve line, then draw line vertically down to the number of half-lives. 75% = 0.5 half-lives have occurred. (had a small estimation range given for this answer 0.45-0.55) 4670years x 0.5 half-lives = 2,235 years

Most scientists rejected Alfred Wegener's ideas on continental drift becasue _____.

Wegener couldn't provide a plausible physical mechanism for continental drift. Alfred Wegener provided an abundance of evidence showing that the continents were once connected into a supercontinent called Pangaea. He published this in a book titled The Origin of Continents and Oceans, and this book was widely read both in German and in translations. The biggest reason for the rejection of the continental drift hypothesis was the lack of a plausible physical mechanism for how the continents could moved through the oceans. Wegener died in Greenland in 1930, but this was 16 years after he published his book and by this time most scientists had already rejected his ideas. Other scientists continued to promote his ideas after his death but they were still rejected unit the late 1950s and early 1960s when sea-floor spreading provided the mechanism for plate tectonics.

The rate of movement (or velocity) of most tectonic plates averages ______ .

a few centimeters per year Plates move between 1 and 20 centimeters per year, with most plates moving only a few centimeters per year.

Which of the following natural disasters has the highest probability (most likely) of causing a 1,000-fatality event each year somewhere in the world and would be considered a great natural disaster.

a tropical cyclone (e.g. hurricane, cyclone, or typhoon) Great earthquakes and tropical cyclones are most likely to cause great natural disasters, but tropical cyclones occur very frequently whereas great earthquakes occur less frequently. So tropical cyclones is the best answer here.

Which of the following ideas/concepts/models are examples of scientific hypotheses?

all of these are scientific hypotheses

Evidence from paleomagnetism, sea floor magentism, and the ocean drilling program has demonstrated that oceans are actually _____ than the continents and the oldest ocean crust is about _____ years old.

younger, 200 million Most of the ocean crust (or lithosphere) is younger than the continents and is younger than 200 million years old (very small area that old). The evidence for this is both indirect evidence from sea-floor magnetic patterns correlated to the paleomagnetic time scale, and direct evidence from dating sediment and ocean crust basalt collected by the deep-sea drilling program which started in the 1960s.