GEOL 3950 Test 2

Continents include rocks much older than the oldest oceanic rocks because the continents are too buoyant to get subducted

True or False

Faults are surfaces within the rock layers of the crust and upper mantle across which there have been shearing motion offsets.

True or False

Humans are constructing megacities in regions where destructive earthquakes have happened in the past.

True or False

India used to be connected to Africa and Antarctica.

True or False

Mid-Ocean Ridges are high volcanic mountains on the sea-floor, with the surrounding abyssal plains being deeper because the lithospheric rock densifies and sinks as it cools over time.

True or False

The San Andreas Fault is the longest active fault in California.

True or False

The western margin of California was a subduction zone up until about 30 million years ago when North America began to override the Pacific rise, changing the boundary into the horizontal shearing of the San Andreas fault.

True or False

Water from subducted sediments plays an important role in the melting of upwelling hot materials beneath ocean ridges.

True or False

Early Japanese myths about the causes of earthquakes involved which one of the following

a) Godzilla b) Giant Catfish c) Giant Dragons d) Giant Moths

If the hanging wall moves downward with respect to the foot wall, we describe the faulting as

a) Thrust Faulting b) Strike-Slip Faulting c) Normal Faulting d) Oblique Faulting

Which of the following would you expect to be least associated with volcanoes:

a) magma b) fossils c) island arc d) plume

Know the major types of plate boundaries, and what types of earthquakes and volcanoes are found at each.

divergent, convergent, and transform Divergent- occurs when two tectonic plates move away from each other. Along these boundaries, lava spews from long fissures and geysers spurt superheated water. Frequent earthquakes strike along the rift. The African Rift Valley in East Africa is an example of this occurrence. Volcanos: Shield volcanoes often form along divergent plate boundaries. Convergent-When two plates come together, it is known as a convergent boundary. The impact of the two colliding plates buckles the edge of one or both plates up into a rugged mountain range, and sometimes bends the other down into a deep seafloor trench. A chain of volcanoes often forms parallel to the boundary, to the mountain range, and to the trench. Powerful earthquakes shake a wide area on both sides of the boundary.The Washington-Oregon coastline of the United States is an example of this type of convergent plate boundary. Volcanos: Composite cone volcanoes (or Stratovolcanoes) are found along convergent Boundaries Transform- Two plates sliding past each other forms a transform plate boundary. Natural or human-made structures that cross a transform boundary are offset—split into pieces and carried in opposite directions. Rocks that line the boundary are pulverized as the plates grind along, creating a linear fault valley or undersea canyon. As the plates alternately jam and jump against each other, earthquakes rattle through a wide boundary zone. In contrast to convergent and divergent boundaries, no magma is formed. Thus, crust is cracked and broken at transform margins, but is not created or destroyed.California's San Andreas fault is a transform boundary Volcanos: Usually no Volcanos