EAPS 105 TEST PAPER ANSWERS AND QUESTIONS
SET A+
✔✔What a magnetosphere is - ✔✔the region where a planet's magnetic field is the
predominant magnetic field
✔✔Why Venus does not have a magnetic field - ✔✔it spins too slowly (243 Earth days
per rotation) to organize convection in its liquid iron core into coils
✔✔Why Jupiter and Neptune have magnetic fields - ✔✔Jupiter's moon, Io, provides a
portion charged particles to Jupiter's magnetosphere, Jupiter has a liquid metallic
hydrogen core, Neptune has chemistry of liquid ammonia/methane ice that cause the
field
✔✔The types of volcanism observed on each terrestrial planet - ✔✔mid-ocean ridges
and subduction zones in planets with tectonic plates, hot spots in planets without
tectonic plates
✔✔Know that mantles are mostly not melted rock (magma) - ✔✔vast majority of the
mantle in all terrestrial planets and all moons is below its melting temperature.
✔✔Know the three ways to cause hot, but unmelted rocks, to melt - ✔✔increase
temperature, decrease pressure, add water to the mineralogy (called hydration-induced
melting)
✔✔What causes rocks to melt in each of the three types of volcanism on Earth -
✔✔increase in temperature, decrease pressure, add water to the mineralogy to break
long molecular chain
✔✔How hotspots cause volcanic chains - ✔✔as tectonics move over a hot spot,
volcanoes lose their source of magma and become extinct, leaving a chain (or hotspot
track) of volcanoes
, ✔✔Why Olympus Mons on Mars is so big - ✔✔gravity on Mars is 1/3 that of Earth, Mars
does not have plate tectonics, Mars does not have significant erosion process
✔✔What type of viscosity/gas content combination leads to explosive versus effusive
volcanic eruptions - ✔✔explosive eruptions: high viscosity and high gas content
effusive eruptions: low viscosity and low gas content
✔✔How shield and stratovolcanoes are made - ✔✔shield volcanoes: low viscosity
magma
stratovolcanoes: medium viscosity magma
✔✔Why volcanoes on Venus are relatively flat compared to those on Earth - ✔✔Venus
has a much denser atmosphere
✔✔What happens to gas dissolved in magma as the magma rises close to the surface -
✔✔the pressure is decreased as the magma rises and this dissolved gas expands to
form gas bubbles
✔✔Know the main factors that determine whether a volcano will erupt explosively or
effusively - ✔✔amount of magma, amount of dissolved gases, viscosity of magma
✔✔The different types of explosive volcanic eruptions and their relative explosiveness -
✔✔Hawaiian eruption: <2 km or 6,500 ft
Strombolian eruption: <10 km or 38,800 ft
Vulcanism eruption: <20 km or 65,600 ft
Plinian eruption: <55 km or 180,400 ft
✔✔What a pyroclastic flow is - ✔✔the heavier parts of an explosive eruption that run
down the flank of a volcano at up to 200 mph powered by expanding hat gases at over
1,000 degrees Celsius
✔✔How a caldera forms - ✔✔a large circular depression formed when the surface
collapses into an emptied magma chamber
✔✔The major components of an eruption column and what is going on in each - ✔✔gas
thrust region: ash powered upwards by high pressure from expanding gases
convective ascent region: the buoyancy of hot, low density ash allows it to continue to
rise on convection currents
umbrella region/neutral density level: ash stops rising and spreads out due to the ashes
density equaling the density of the surrounding air
momentum-driven ascent region: rising ash initially overshoots the neutral buoyancy
level
SET A+
✔✔What a magnetosphere is - ✔✔the region where a planet's magnetic field is the
predominant magnetic field
✔✔Why Venus does not have a magnetic field - ✔✔it spins too slowly (243 Earth days
per rotation) to organize convection in its liquid iron core into coils
✔✔Why Jupiter and Neptune have magnetic fields - ✔✔Jupiter's moon, Io, provides a
portion charged particles to Jupiter's magnetosphere, Jupiter has a liquid metallic
hydrogen core, Neptune has chemistry of liquid ammonia/methane ice that cause the
field
✔✔The types of volcanism observed on each terrestrial planet - ✔✔mid-ocean ridges
and subduction zones in planets with tectonic plates, hot spots in planets without
tectonic plates
✔✔Know that mantles are mostly not melted rock (magma) - ✔✔vast majority of the
mantle in all terrestrial planets and all moons is below its melting temperature.
✔✔Know the three ways to cause hot, but unmelted rocks, to melt - ✔✔increase
temperature, decrease pressure, add water to the mineralogy (called hydration-induced
melting)
✔✔What causes rocks to melt in each of the three types of volcanism on Earth -
✔✔increase in temperature, decrease pressure, add water to the mineralogy to break
long molecular chain
✔✔How hotspots cause volcanic chains - ✔✔as tectonics move over a hot spot,
volcanoes lose their source of magma and become extinct, leaving a chain (or hotspot
track) of volcanoes
, ✔✔Why Olympus Mons on Mars is so big - ✔✔gravity on Mars is 1/3 that of Earth, Mars
does not have plate tectonics, Mars does not have significant erosion process
✔✔What type of viscosity/gas content combination leads to explosive versus effusive
volcanic eruptions - ✔✔explosive eruptions: high viscosity and high gas content
effusive eruptions: low viscosity and low gas content
✔✔How shield and stratovolcanoes are made - ✔✔shield volcanoes: low viscosity
magma
stratovolcanoes: medium viscosity magma
✔✔Why volcanoes on Venus are relatively flat compared to those on Earth - ✔✔Venus
has a much denser atmosphere
✔✔What happens to gas dissolved in magma as the magma rises close to the surface -
✔✔the pressure is decreased as the magma rises and this dissolved gas expands to
form gas bubbles
✔✔Know the main factors that determine whether a volcano will erupt explosively or
effusively - ✔✔amount of magma, amount of dissolved gases, viscosity of magma
✔✔The different types of explosive volcanic eruptions and their relative explosiveness -
✔✔Hawaiian eruption: <2 km or 6,500 ft
Strombolian eruption: <10 km or 38,800 ft
Vulcanism eruption: <20 km or 65,600 ft
Plinian eruption: <55 km or 180,400 ft
✔✔What a pyroclastic flow is - ✔✔the heavier parts of an explosive eruption that run
down the flank of a volcano at up to 200 mph powered by expanding hat gases at over
1,000 degrees Celsius
✔✔How a caldera forms - ✔✔a large circular depression formed when the surface
collapses into an emptied magma chamber
✔✔The major components of an eruption column and what is going on in each - ✔✔gas
thrust region: ash powered upwards by high pressure from expanding gases
convective ascent region: the buoyancy of hot, low density ash allows it to continue to
rise on convection currents
umbrella region/neutral density level: ash stops rising and spreads out due to the ashes
density equaling the density of the surrounding air
momentum-driven ascent region: rising ash initially overshoots the neutral buoyancy
level
