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