SEISMOLOGY Flashcards
is the study of the generation, propagation and measurement of seismic waves through earth and the sources that generate them.
SEISMOLOGY
The earth’s shape is an
OBLATE SPHEROID
the average specific gravity
of earth is about
5.5
the outer part of the earth is where the life exist.
CRUST OR LITHOSPHERE
is a 2900 km thick layer
MANTLE
Upper Mantle reaching a
depth of about 400 km made of
OLIVINE AND PYROXENE
Lower Mantle made of more
homogeneous mass of
MAGNESIUM, IRON OXIDE AND QUARTZ
SPECIFIC GRAVITY OF MANTLE
5
Core has a radius of
3470 km
INNER CORE HAS A RADIUS OF
1370 Km
the core is composed of
molten iron, nickel, sulfur or silicon
proposed the hypothesis that the continents
had once formed a single landmass before breaking apart and drifting to their present locations.
German Scientist Alfred Wegener (1915)
explains that the lithosphere is broken into seven large (and several smaller) segments called
PLATES
He proposed that a large continent termed Pangae existed in earth around 200 million years ago and was surrounded by an ocean called.
PANTHALASA
WHAT IS THE CONTINENTAL SIZED PLATES
African, American, Antarctic, Indo-Australian, Eurasian
and pacific plate
are areas along the edges of plates move apart from each other
SPREADING RIDGES OR DIVERGENT BOUNDARIES
are formed where the two plates move toward each other. In this process, one plate could slip below the other one or both could collide with each other.
CONVERGENT BOUNDARIES
These boundaries are created when either oceanic lithosphere subducts beneath oceanic lithosphere (ocean-ocean convergence), or when oceanic lithosphere subducts beneath continental lithosphere (ocean-continent convergence).
SUBDUCTION BOUNDARIES
When two plates with continental lithosphere collide, subduction ceases and a mountain range is formed by squeezing together and uplifting the continental crust on both plates,
COLLISION BOUNDARIES
occur along the plate margins where two plate moves past each other without destroying or creating new crust
TRANSFORM BOUNDARIES
is used to describe a discontinuity within rock mass, along which movement had happened in the past.
FAULT
are mappable linear surface features and may reflect subsurface phenomena.
LINEAMENTS
The region on the fault, where rupture initiates is known as the
FOCUS OR HYPOCENTER
is the location on the earth surface vertically above the focus.
EPICENTER
Distance from epicenter to any place of interest is called the
EPICENTRAL DISTANCE
The depth of the focus from the epicenter is the
FOCAL DEPTH
The higher diameter along equator is caused by the higher ________________ generated along the equator due to rotation of earth.
CENTRIFUGAL FORCE
The oceanic crust is constituted by
BASALTIC ROCKS
continental part by
GRANITIC ROCKS
The mantle has an average
temperature of about
2200 DEGREE CELCIUS
The specific gravity of
outer core is about
9-12
The specific gravity of
inner core is
15
create shear stresses at the bottom of the plates which drags them along the surface of earth.
CONVECTION CURRENTS
interior portion of a plate is usually tectonically quiet, earthquakes also occur far from plate boundaries
INTRA-PLATE EARTHQUAKES
The earthquake that occurs at a plate boundary is known as
INTER-PLATE EARTHQUAKES
It could be a fault, a joint or any other linear geological phenomena.
LINEAMENT
is the direction of a horizontal line on the surface of the fault
STRIKE
measured in a vertical plane at right angles to the strike of the fault
DIP
The vertical shift along a fault plane is called
THROW
the horizontal displacement is termed as
HEAVE
the slippage occurred along the dip of the fault
DIP-SLIP FAULT
the movement has taken place along the strike
STRIKE-SLIP FAULT
The movement occurs diagonally across the fault plane
OBLIQUE SLIP FAULT
the hanging wall has been displaced downward relative to the footwall
NORMAL FAULT
the hanging wall has been displaced upward relative to the footwall
REVERSE FAULT
the foot or the hanging wall do not move up or down in relation to one another
WRENCH FAULT
which are a subdivision of
reverse faults, tend to cause severe earthquakes
THRUST FAULT
As the plate try to move relative to each other, strain energy gets built up along the
boundaries
ELASTIC REBOUND THEORY
