Geology Lab Exam 1

artificial fill

sand and rock texture-buildings would fall over-nothing stable enough to hold them

modern barrier island

beach sand texture-walls would fall down-not sturdy enough

prime meridian

longitude

equator

latitude

focus

point beneath the surface where the energy is released from

sedimentary rocks

Along the coast, waves carry sand out into deeper, quieter water, where it accumulates and gradually becomes buried. A rock formed from sand grains cemented together is

metamorphic

The broad tundra plains of Northern Canada expose gray, massive rock that formed many kilometers below a mountain belt. This rock, exposed only after the overlying rock was stripped away, is

igneous rocks

Thick flows of glowing red lava engulf farms and villages on the flanks of Mount Etna, a volcano in Sicily, Italy. The cold, black, rock formed when these flows are cooled enough to walk on is

hotspots

a mantle plume forms and creates volcanoes until the string of magma breaks

liquefaction

a process where a seismic vibration causes friction between sand grains in waterlogged sediment

earthquakes

caused by masses of rock suddenly shifting below the earth's surface

summerville fault

charleston isn't located on an active plate boundary but we have earthquakes here because of the ________

rift zones

continental lithosphere stretches and breaks apart

ancient barrier island

dense, water resistant sand texture-walls shook but remained standing-sand is thicker and has more support

edges of faults

earthquakes typically occur ______

intermediate felsic

erupts explosively and violently, sticky and viscous, associated with composite volcanoes

mafic

erupts gently, runny and fluid magma, associated with shield volcanoes

course grained

grains large enough so you can identify the minerals present

cooper marl

hard, clay or puddy texture- best for building-most stable during an earthquake

west coast of africa

has a broad continental shelf, isn't near any trenches and very few earthquakes happen there

west coast of south america

has a narrow continental shelf is close to the peru-chile trench and is part of the pacific ring of fire

composite volcano

high viscosity and highly explosive; built on altering layers of pyroclastic flow; associated with convergent plate boundaries; continental crust

three

how many seismographs are necessary to determine the location of the epicenter of an earthquake?

must be destroyed

if new crust is being formed at spreading centers, then what must happen to the old crust?

map scale

indicates how much an area has been scaled down so we can relate inches or centimeters on the map to real distances on the ground

fine grained

individual grains are too small to be seen with the naked eye or identified with a hands lends

latitude

lines that circle the globe from east to west. it is the angular distance of a place, north or south of earth's equator

passive continental margin

located on the north america, broad continental shelves

active continental margin

located on the west coast of north america, bc narrow continental shelves

unstable

man-made land is more ______ during an earthquake because the bedrock will separate and become exposed

magma

molten rock below earth's surface

lava

molten rock that has erupted onto the surface

proportional scale

most accurate way to describe a scale. one that tells exactly how much the ground has been scaled down to the map

Greenwich, UK

the prime meridian passes through what city and country?

divergent boundaries

plates slide away from each other; crust is young; fissure volcanism; has a normal fault and geologic features=ridges

transform boundaries

plates slide past each other and the lithosphere is neither formed nor consumed; has a strike slip fault and geologic features=fracture zones

convergent boundaries

plates slide toward each other; crust is old; composite volcanism; has a reverse fault and geologic features= trenches, volcanic island arches, mountain chain, benioff zones

epicenter

point on the surface directly above the focus

subduction zones

sediment on the down going slab is scraped off and incorporated in the accentionary prism, along with sediment deposited

shield volcano

shallow slopes and built upon many lava flows; associated with hotspots; oceanic crust; basalt lava flow

longitude

the lines that run north to south. it is the angular distance of a place east to west of the meridian

trenches

the oldest crust is closest to ______

ridges

the youngest crust is closest to _______

60 minutes

there are ______ minutes in each degree of latitude

60 seconds

there are ______ seconds in each minute

modern barrier and artificial fill

these foundations experience liquefaction because they are sand based

p waves

this is the fastest of the waves; travels the tastes

water

this plays an important role in liquefaction because it reduces the sediment so that it loses its ability to support

surface waves

this wave causes the most destruction because they are the slowest and largest

verbal scale

used on many road maps, uses words like "1 inch equals approx. 6.7 miles" to describe scaling of map and real distances

graphical scale

used to express the same relation as a verbal scale using a bar scale

seismic waves

waves that travel along the earth's surface