PHYSICAL GEOLOGY SCRIPTED CORRECT ANSWERS
AND QUESTIONS SET A+
✔✔Characteristics of Mafic lavas - ✔✔-poor in SiO2
-less viscous
-Melt at higher temps
-basaltic
-pyroxene, olivine, plagioclase rich
✔✔Characteristics of felsic lavas - ✔✔-Rich in SiO2
-More viscous
-melts at higher temps
✔✔Places where volcanism is common - ✔✔-MOR (MORB forms here)
-Continental Arcs
-Oceanic Arcs
✔✔MOR Volcanism - ✔✔-characterized by decompression melts of mantle peridotite
-This peridotite makes olivine/pyroxine-rich magma.
✔✔Pillow basalt - ✔✔Occur at eruptions along mid-ocean ridges. Outer layer of magma
chills and solidifies in cold seawater
✔✔Continental arc volcanism; Oceanic arc.... - ✔✔forms chains of volcanoes where a
subducint plate meets the continental crust; oceanic forms where oceanic subducting
plates meet
✔✔Pyroclastic lava flows - ✔✔-fast moving mix of cinders and ash from explosive
volcanism
-high volatile content and and hi SiO2 content
-As magma rises, volatiles come out of the magma (degassing) forming gas bubbles
-This causes buoyancy that accelerates flows upwards
, ✔✔Pyroclastic flows result from, and create.... - ✔✔H2o and volatile rich magma that
forms bigger bubbles as it rises causing explosions; create high porosity rocks like
pumice
✔✔Damaging effects of volcanism - ✔✔-pyro: move fast and are v hot
-effusive: property damage
-Ash: damage machinery, aircraft threat
✔✔lahar - ✔✔An avalanche of volcanic water and mud down the slopes of a volcano
✔✔Volcanic monitoring - ✔✔Short-term predictions are advanced but longterm is hard
to predict. We can tell from seismicity, gas emissions and shape of volcanos from
satellite monitoring
✔✔Reverse fault - ✔✔a type of fault where the hanging wall slides upward; caused by
compression in the crust
✔✔Normal fault - ✔✔A type of fault where the hanging wall slides downward; caused by
tension in the crust
✔✔Thrust fault - ✔✔a reverse fault with a dip less than 45 degrees, normally about 10-
15 degrees
✔✔strike slip - ✔✔a type of fault where rocks on either side move past each other
sideways with little up or down motion
✔✔Quake-inducing movements are a result of - ✔✔-brittle failure
✔✔The two primary types of stress are - ✔✔1. tensile (normal)
2. compressional (reverse)
✔✔An oblique fault - ✔✔has a combination of vertical and horizontal movement
✔✔Magnitude measurements - ✔✔-richter scale is now outdated (only referenced so-
cal measurements)
-now we use Moment-magnitude scale developed by Hiroo Kanamori
✔✔Shear waves are polarized into: - ✔✔- P- waves (Spring-like)
-S- wave (perpendicular to direction of wave)
- Rayleigh waves (vertical)
-Love (horizontal displacement of surface)
✔✔Are p or s waves faster - ✔✔p-waves are faster
AND QUESTIONS SET A+
✔✔Characteristics of Mafic lavas - ✔✔-poor in SiO2
-less viscous
-Melt at higher temps
-basaltic
-pyroxene, olivine, plagioclase rich
✔✔Characteristics of felsic lavas - ✔✔-Rich in SiO2
-More viscous
-melts at higher temps
✔✔Places where volcanism is common - ✔✔-MOR (MORB forms here)
-Continental Arcs
-Oceanic Arcs
✔✔MOR Volcanism - ✔✔-characterized by decompression melts of mantle peridotite
-This peridotite makes olivine/pyroxine-rich magma.
✔✔Pillow basalt - ✔✔Occur at eruptions along mid-ocean ridges. Outer layer of magma
chills and solidifies in cold seawater
✔✔Continental arc volcanism; Oceanic arc.... - ✔✔forms chains of volcanoes where a
subducint plate meets the continental crust; oceanic forms where oceanic subducting
plates meet
✔✔Pyroclastic lava flows - ✔✔-fast moving mix of cinders and ash from explosive
volcanism
-high volatile content and and hi SiO2 content
-As magma rises, volatiles come out of the magma (degassing) forming gas bubbles
-This causes buoyancy that accelerates flows upwards
, ✔✔Pyroclastic flows result from, and create.... - ✔✔H2o and volatile rich magma that
forms bigger bubbles as it rises causing explosions; create high porosity rocks like
pumice
✔✔Damaging effects of volcanism - ✔✔-pyro: move fast and are v hot
-effusive: property damage
-Ash: damage machinery, aircraft threat
✔✔lahar - ✔✔An avalanche of volcanic water and mud down the slopes of a volcano
✔✔Volcanic monitoring - ✔✔Short-term predictions are advanced but longterm is hard
to predict. We can tell from seismicity, gas emissions and shape of volcanos from
satellite monitoring
✔✔Reverse fault - ✔✔a type of fault where the hanging wall slides upward; caused by
compression in the crust
✔✔Normal fault - ✔✔A type of fault where the hanging wall slides downward; caused by
tension in the crust
✔✔Thrust fault - ✔✔a reverse fault with a dip less than 45 degrees, normally about 10-
15 degrees
✔✔strike slip - ✔✔a type of fault where rocks on either side move past each other
sideways with little up or down motion
✔✔Quake-inducing movements are a result of - ✔✔-brittle failure
✔✔The two primary types of stress are - ✔✔1. tensile (normal)
2. compressional (reverse)
✔✔An oblique fault - ✔✔has a combination of vertical and horizontal movement
✔✔Magnitude measurements - ✔✔-richter scale is now outdated (only referenced so-
cal measurements)
-now we use Moment-magnitude scale developed by Hiroo Kanamori
✔✔Shear waves are polarized into: - ✔✔- P- waves (Spring-like)
-S- wave (perpendicular to direction of wave)
- Rayleigh waves (vertical)
-Love (horizontal displacement of surface)
✔✔Are p or s waves faster - ✔✔p-waves are faster
