SFSU ERTH 110

Which statement below best compares the lithosphere to the asthenosphere according to the lecture?

The lithosphere is a brittle solid and the asthenosphere is a ductile solid.

Which statement below best compares the crust to the lithosphere according to the lecture.

The lithosphere is defined by its physical property of being brittle. The crust is defined by its composition (felsic, intermediate and mafic)

Deep Focus Earthquakes

U

Why did you choose the answer you did for question 3? Choose the best answer below:

. The wet conditions of the tropics allows the chemical reactions of weathering to take place at all, while the heat in this region speeds up the process of weathering.

Las Vegas, NV:

100 mm

Look at Figure 2. How many iron cations were you able to draw in for each silicon-oxygen tetrahedron (not the entire chain)? Choose a silicon-oxygen tetrahedron that is sitting in the middle of the chain, not the ends.

2

Eureka, CA:

285 mm

Click on "Convert S-P Interval". Read the information on "Determining the Earthquake Distance". It takes an S-wave approximately 70 seconds to travel 300 km. How long does it take the P-wave to travel this same distance? Choose the best answer below

39 seconds

Use the S-P graph at the bottom of the webpage and the estimates you made for the S-P travel times for the three seismograms. Choose the closest number that represents the closest distance in the space below: Eureka, CA:

478 km

Eureka, CA:

49 seconds

Elko, NV:

60 mm

Las Vegas, NV:

623 km

Las Vegas, NV:

64 seconds

The page shows a nomogram with three lines representing the data you provided. Type in your estimate for the earthquake in the box provided on the webpage and click on "Confirm Magnitude". Choose the magnitude below that most closely represents the magnitude for this earthquake.

7.1

Elko, NV:

703 km

Elko, NV:

72 seconds

How does a conglomerate differ from a breccia?

A conglomerate is made up of cemented rounded gravel-sized grains and a breccia is made up of cemented angular gravel-sized grains

What are the key differences between a scientific theory and a scientific law/principle according to the lecture? Choose from the following:

A law explains the process of a phenomenon, but not why it occurs like a theory does.

What is true about the difference between a mineral and a rock?

A rock is generally made up of an aggregate of minerals, but this is not a requirement. Rocks can also be made up of non-mineral matter.

What is a silicon-oxygen tetrahedron?

A silicon surrounded by four oxygen

What are the key differences between a scientific hypothesis and a scientific theory according to the lecture? Choose from the following:

A theory is an accumulation of many well-proven and well-accepted hypotheses that explain why phenomenon occurs. Correct

Which layer(s) from the choices below are defined by physical properties and could be considered a ductile solid?

Asthenosphere & Mesosphere

Of the choices below, which one represents 100% of the Earth's mantle

Asthenosphere, Mesosphere and the ultramafic section of the Lithosphere.

Which of the following rocks below is a mafic extrusive igneous rock?

Basalt

What mineral is limestone made from?

Calcite (CaCO3)

A long, narrow linear or gently curving deep trench, earthquakes to depths of several hundred kilometers, and volcanoes paralleling the trenches on continents.

Continent-Ocean Convergent Boundary

Which of the layers listed below is defined as a layer by composition?

Core

A long, linear rise in the sea-floor with earthquakes and volcanic activity found along its ridge.

Divergent Boundary

What climatic region would you expect to find the lowest rates of weathering?

Dry and hot (desert) region

If quartz is present in an igneous rock, what composition must it be?

Felsic

How many iron cations were you able to draw in for the single silicon-oxygen tetrahedron (Figure 1)?

Four

Which rock below is the intrusive equivalent to basalt?

Gabbro

According to the textbook reading for this week (Module 1), which definition below would be the best definition of Geology?

Geology is the scientific study of the nature, origin and evolution of the Earth and other terrestrial bodies.

What viscosity must the higher parts of a stratovolcano be, where its sides steepen up?

High viscosity

In terms of temperature, mafic magma is the [hottest] [coldest] when compared to more felsic magma.

Hottest

Which type of wave below can travel through solids and liquids and is similar to a sound wave?

P-waves

What composition of magma is involved in the construction of the higher parts of a stratovolcano? Choose the best answer(s):

Intermediate Felsic

A rock that crystallizes at depth from magma deep underground is referred to as:

Intrusive

Read the section on "Magnitude Explained". What is the magnitude of an earthquake? Choose the best answer from the choices below

It is an estimate of the total amount of energy released by an earthquake

Choose the region "San Francisco area" for your simulation of an earthquake and click "submit choice". What does the S-P interval represent exactly? Choose the best answer below:

It is the time interval between the arrival of the P-wave and the arrival of the S-wave at a seismic station.

Which of the layers listed below is defined as a layer by its physical properties

Lithosphere

What viscosity must the base of a stratovolcanoes lava be, when it has broad, non-steep sides?

Low viscosity

When a volcano is at least partially created by its lava flows, the viscosity of that lava can determine its steepness. What viscosity must a shield volcanoes lava be, with its broad, non-steep sides?

Low viscosity

Higher temperature magmas will have a __________ viscosity.

Lower

What composition of magma is basalt made from primarily?

Mafic

What composition of magma is primarily involved in the construction of a shield volcano?

Mafic

What composition of magma makes up the base of a stratovolcano?

Mafic

The Richter magnitude determination is based on measurements made on seismograms. Two measurements are needed. What are they?

Maximum amplitude of the seismic waves and the S-P time interval.

A long, narrow linear or gently curving deep trench, earthquakes to depths of several hundred kilometers, and volcanoes paralleling the trenches as islands.

Ocean-Ocean Convergent Boundary

What mineral does Figure 1 represent?

Olivine

Which layer defined by physical properties is considered a liquid

Outer Core

Which layer from the choices below generates Earth's magnetic field?

Outer Core

Which of the following rocks below is an ultramafic intrusive igneous rock?

Peridotite

What makes a cinder cone steep-sided?

Piling up of cinders during an eruption

Why are there more silicon relative to oxygen in Figure 2?

Polymerization has occurred in Figure 2, where the oxygen are being shared between tetrahedrons

An igneous rock that is made up of large and small crystals is called:

Porphyritic

Which of the following rocks below is a glassy rock?

Pumice

What mineral does Figure 2 represent?

Pyroxene

Which of the following minerals from the choices below share all oxygen in the silicate structure.

Quartz

According to the lecture, what energy source is Earth using primarily for its internal processes?

Radioactive decay

Viscosity is defined as the __________ to flow.

Resistance

Which of the following rocks below is a felsic extrusive igneous rock?

Rhyolite

How does a shale differ from a sandstone?

Shale is compacted mud-sized grains and sandstone is cemented sand-sized grains

What is a single-chain silicate?

Silicon-oxygen tetrahedrons that are connected in a chain because they are sharing oxygen.

According to the lecture, what energy source is Earth using primarily for its external/surficial processes?

Solar energy

Where do earthquake waves originate from?

The Focus

What is Weathering?

The chemical or mechanical breakdown of rock into smaller components.

Type in your answers above into the boxes provided on the webpage and hit "Find Epicenter". The next screen will be a map showing circles. What are these circles themselves individually depicting?

The distance between the seismic recording station and the possible earthquake epicenter

What is Erosion?

The transportation of sediment by water, wind, ice or gravity

A land or seafloor region with many quakes right along the boundary line. Depth of the earthquakes are shallow and the topography is not impressive (no real large mountains or valleys). Volcanic activity is not common along this boundary.

Transform Boundary

The silicates are the most common minerals in the Earth.

True

Convergent Plate Boundary

U

Transform Plate Boundary

W

Shallow Focus Earthquakes

W, X, Y

What climatic region would you expect to find the highest rates of weathering?

Warm and wet (tropics/rain forest) region

Why did you choose the answer you did for question 5?

With very little water present in a desert region, weathering will need to be slowest there as a result

Divergent Boundary

X

Ocean Trench

Y