ESC Final Exam Flashcards
A tsunami
may be just a broad, gentle swelling out at sea but grows as it approaches shore.
Aftershocks are usually
much weaker than the mainshock.
Andrija Mohorovicic discovered the crust-mantle boundary, which is now named after him, because he realized that
P-waves were refracted at the boundar
Earthquake prediction is not highly reliable, but geologists do know
more earthquakes happen along plate boundaries than happen at intraplate locations.
Earthquakes in California are
due to stick-slip behavior along the San Andrea fault.
Examining sedimentary bedding in a particular geologic area reveals disrupted layers that formed 260, 820, 1,200, 2,100, and 2,300 years ago. Assuming that all the earthquakes that have occurred in this area are represented by these disrupted layers, what is the recurrence interval of earthquakes in this area?
510 years
Interpret the travel-time curve shown. Approximately how many minutes elapsed between the arrival of the first P-wave and the arrival of the first S-wave at Station 3?
7
Liquefaction
can affect sand layers below the ground surface and cause them to erupt as sand volcanoes or sand boils.
Long-term earthquake predictions
are based on the study of historic recurrence intervals.
One difference between P- and S-waves is that
only P-waves can travel through a liquid.
The 2010 Haiti earthquake was so destructive because
of poor construction standards that caused many buildings to collapse.
The Modified Mercalli Intensity scale measures
earthquake damage.
The P-wave shadow zone marks the
core-mantle boundary.
The Richter scale
measures the size of earthquake by the amount of ground motion.
The S-wave shadow zone indicates
the outer core is liquid.
The areas shown in gray occur because
P-waves are refracted at the core-mantle boundary.
The earthquake foci pattern east of Australia and just north of New Zealand indicates which tectonic setting?
Convergent plate boundary
The locations of major earthquakes
are usually along plate boundaries.
To find the location of an earthquake’s epicenter, you need to calculate the distance from the epicenter to ____ different seismometer stations.
3
When a fault slips and the rock units on either side return to their original shape by generating vibrations, it is called
elastic rebound.
Which of the following is a good technique for building safer structures in an earthquake zone?
Use wood-frame construction.
Which peripheral hazard of earthquakes caused the damage shown in the photo?
Landslide
Which type of wave is a compressional body wave?
P-wave
A radioactive isotope of the element potassium decays to produce argon. If the ratio of the number of argon to potassium atoms is found to be 7:1, how many half-lives have occurred since the sample of radioactive potassium started to decay?
3
An area of slightly dipping sedimentary rock layers has large inclusions and is intruded by an igneous dike. Using the basic principles for determining relative ages you can infer that the
sedimentary rock “baked” by the igneous intrusion is older than the intrusion.
An organism is most likely to be fossilized if it
dies in an oxygen-poor environment.
Footprints, feeding traces, burrows, and dung are considered to be
trace fossils.
Geologists estimate that the Earth is 4.54 billion years old, based on
isotopic dating of meteorites from the first differentiated bodies of the Solar System.
If a sandstone contains pieces of basalt, then the sandstone is younger than the basalt according to the principle of
inclusions.
If you equate all Earth history to one calendar year, our species (Homo sapiens) would appear on
11 P.M. on New Year’s Eve.
In 1815, William Smith correlated strata from many locations and plotted them on paper to show the spatial distribution of rock units on Earth’s surface. This document was the first modern
geologic map.
In the cross-section, identify the oldest feature in the sequence.
Bed 1
In the cross-section, identify youngest event in the sequence.
Erosion of the land surface
Petrified wood is an example of a
permineralized fossil.
The age of beds exposed in one location is related to the age of beds exposed in another location based on similarities in rock type between the two locations. What is this process called?
Lithologic correlation
The boundary surface between any two stratigraphic formations is called a
contact.
The concept that times of relative stability in the number and identity of species alternate with times of rapid change is called
punctuated equilibrium.
The determination that one feature is older or younger than another feature, without calculating their actual ages, is known as
relative dating.
The evolution of life is tied to the geologic column, with the first life appearing in the _________, the ________ referred to as the Age of Mammals, and the _________ referred to as the Age of Dinosaurs.
Archean Eon, Cenozoic Era, Mesozoic Era
The image shows a stratigraphic section of the Grand Canyon. Between which two groups is there an angular unconformity?
Unkar Group and Tapeats Sandstone
The observations of _____________ led to the principle of uniformitarianism.
James Hutton
Uniformitarianism means
geologic processes that operate today operated in the past at about the same speed.
What type of unconformity is illustrated by the sequence?
Angular unconformity
What type of unconformity is illustrated by the sequence?
Nonconformity
Which of the following accurately ranks the subdivisions of geologic time in order from largest to smallest?
Eon, era, period, epoch
Which of the following correctly lists the time divisions shown from oldest to youngest?
Proterozoic Eon, Paleozoic Era, Mesozoic Era, Cenozoic Era
Which of the following is NOT true about William Smith’s observations?
He noted that a fossil species could disappear then reappear in much younger strata.
Which principle states that in an undisturbed sedimentary sequence, the oldest layer lies at the bottom and the youngest layer at the top?
Principle of superposition
A seal rock
is a necessary component of an oil trap.