Geol 1103 Midterm Exam: BRCC

According to the __________, earthquakes occur when ___________ accumulates until it exceeds the strength of the rock.

Elastic Rebound Theory / stress

The Richter scale for earthquakes is an exponential scale, meaning the Japanese 2011 earthquake of magnitude 9 was how many times stronger than the Haitian 2010 earthquake of magnitude 7:

100 times

If a rock body is subjected to a force, and it deforms by breaking or faulting, that represents ______________ deformation

Brittle

Alfred Wegener developed what concept that lead to the Theory of Plate Tectonics:

Continental Drift

The tectonic boundaries with the deepest focus earthquakes would be:

Convergent boundaries

What are the most deadly phenomena of earthquakes from epicenters in or near an ocean:

Tsunami waves

Pangea is a name for:

A former supercontinent that was made up of all present continents

The United States mainland is characterized by which of the following tectonic margins:

A transform margin characterized by frequent strong earthquakes, a convergent margin with deep sea trench and volcanoes on the mainland, and a passive continental margin characterized by deep sedimentary deposits.

The type of lava that forms at the highest temperatures is:

Basalt

The type of lavas found at mid-ocean ridges and oceanic hotspots like Hawaii are:

Basalt

What volcanic rock type would spread out a long distance from its source, compared to other lavas?

Basalt, because it has a lower viscosity than other lavas

Oceanic crust always subducts below continental crust because it is:

Composed of denser rocks

Seismic P waves are also known as:

Compression waves

A thrust fault indicates that the rocks were deformed under what type of force:

Compressional

Which of the following statements about the explosiveness of volcanic eruptions is true?

Explosiveness increases as the silica content of the lava increases

Igneous rocks with very small / microscopic crystals or that are mostly glass are typically:

Extrusive igneous rocks

If an igneous rock contains mostly quartz, it's composition is considered to be:

Felsic

Granite rocks that form mountains on continental crust (and are favorites for counter tops!) are what types:

Felsic/Intrusive

The actual location on a fault plane where the rupture occurs that causes an earthquake is called the:

Focus

Geology is different than physics or chemistry because?

Geology is a diachronous science, so the geological record has been unique through time in any one location

Geology/Earth Science

Is a process of observing contemporary Earth materials and the rock record; creating and testing hypotheses to explain the processes that form these different rocks types; and relating these to the development of the Earth through time.

Major earthquakes of magnitudes greater than 8 on the Richter scale are typically related to:

Subduction zones, Convergent plate boundaries, and the Pacific "Ring of Fire"

A geophysicist can determine the distance between a seismograph and an earthquake's epicenter by measuring the elapsed time between the arrival of the ______ and ______ at a seismograph.

P waves and S waves

Basaltic lava flows in Hawaii that move like oozing molasses and form a smooth, ropey surface are called:

Pahoehoe

At convergent plate tectonic margins:

Plates come together and oceanic crust is recycled back into the mantle.

At divergent plate boundaries:

Plates move apart and new lithosphere is created

Volcanoes with felsic composition lavas usually form which of the following landforms:

Stratovolcanoes

20th century observations (1920's to 1960's) along mid-ocean ridges went against older notions of the nature of the ocean because?

The seafloor was youngest in the middle and composed of volcanic rock, there was almost no sediment in the middle of the ocean, and the ocean was shallower in the middle than along the sides of the ocean.

Coarse-textured igneous rocks have large crystals because: Correct!

They have cooled slowly.

How do geomagnetic isochrons on the ocean seafloor indicate where there is a faster rate of spreading at a mid-ocean spreading center than others:

Where isochrons are wider and farther apart