LOMA ACTUAL EXAMINATION TEST 2026
COMPLETE QUESTIONS AND SOLUTIONS
GRADED A+
◉ Extrusive igneous rock. Answer: Forms at or near the surface
when magma erupts and cools quickly, producing small or no
crystals.
◉ Pluton. Answer: A general term for any body of intrusive igneous
rock that formed underground.
◉ Batholith. Answer: A very large pluton (more than 100 km² in
area).
◉ Example of a batholith. Answer: The Sierra Nevada Batholith in
California.
◉ Low viscosity fluids. Answer: Flows easily; examples include
water, mafic lava, and hot maple syrup.
◉ High viscosity fluids. Answer: Flows slowly; examples include
molasses, felsic lava, and cold honey.
,◉ Factors controlling viscosity of magma. Answer: Temperature,
composition (mafic magma has low viscosity, felsic magma has high
viscosity), and water content.
◉ Effusive eruption. Answer: Characterized by low viscosity magma
(mafic, hot) that flows easily as pahoehoe or aa; typically occurs in
shield volcanoes.
◉ Example of an effusive eruption. Answer: Mauna Kea or Kilauea in
Hawaii.
◉ Pyroclastic eruption. Answer: Characterized by high viscosity
magma (felsic, cool) that ejects tephra (ash, blocks, pumice);
typically occurs in composite or stratovolcanoes.
◉ Example of a pyroclastic eruption. Answer: Mount Rainier or
Mount Fuji.
◉ Influence of viscosity on volcanic eruption type. Answer: Low
viscosity magma allows gas to escape easily leading to effusive
eruptions; high viscosity magma traps gas leading to explosive
eruptions.
◉ Plate tectonic setting influence on eruptions. Answer: Hot spots
produce mafic, low-viscosity magma leading to effusive eruptions;
, subduction zones produce felsic, high-viscosity magma leading to
explosive eruptions.
◉ Volcanoes associated with hotspot. Answer: Shield volcanoes (e.g.,
Kilauea, Mauna Kea).
◉ Volcanoes associated with subduction zones. Answer: Composite
volcanoes (e.g., Mount St. Helens, Mount Rainier).
◉ Continental hotspot volcanoes. Answer: Caldera-forming
volcanoes (e.g., Yellowstone).
◉ Hazard. Answer: A natural event that could cause harm (e.g.,
eruption, landslide, lahar).
◉ Risk. Answer: The likelihood that harm will occur to people or
property from a hazard.
◉ Example of a hazard. Answer: Pyroclastic flow from Mount
Rainier.
◉ Example of a risk. Answer: High risk for towns built on old lahar
deposits below the volcano.
COMPLETE QUESTIONS AND SOLUTIONS
GRADED A+
◉ Extrusive igneous rock. Answer: Forms at or near the surface
when magma erupts and cools quickly, producing small or no
crystals.
◉ Pluton. Answer: A general term for any body of intrusive igneous
rock that formed underground.
◉ Batholith. Answer: A very large pluton (more than 100 km² in
area).
◉ Example of a batholith. Answer: The Sierra Nevada Batholith in
California.
◉ Low viscosity fluids. Answer: Flows easily; examples include
water, mafic lava, and hot maple syrup.
◉ High viscosity fluids. Answer: Flows slowly; examples include
molasses, felsic lava, and cold honey.
,◉ Factors controlling viscosity of magma. Answer: Temperature,
composition (mafic magma has low viscosity, felsic magma has high
viscosity), and water content.
◉ Effusive eruption. Answer: Characterized by low viscosity magma
(mafic, hot) that flows easily as pahoehoe or aa; typically occurs in
shield volcanoes.
◉ Example of an effusive eruption. Answer: Mauna Kea or Kilauea in
Hawaii.
◉ Pyroclastic eruption. Answer: Characterized by high viscosity
magma (felsic, cool) that ejects tephra (ash, blocks, pumice);
typically occurs in composite or stratovolcanoes.
◉ Example of a pyroclastic eruption. Answer: Mount Rainier or
Mount Fuji.
◉ Influence of viscosity on volcanic eruption type. Answer: Low
viscosity magma allows gas to escape easily leading to effusive
eruptions; high viscosity magma traps gas leading to explosive
eruptions.
◉ Plate tectonic setting influence on eruptions. Answer: Hot spots
produce mafic, low-viscosity magma leading to effusive eruptions;
, subduction zones produce felsic, high-viscosity magma leading to
explosive eruptions.
◉ Volcanoes associated with hotspot. Answer: Shield volcanoes (e.g.,
Kilauea, Mauna Kea).
◉ Volcanoes associated with subduction zones. Answer: Composite
volcanoes (e.g., Mount St. Helens, Mount Rainier).
◉ Continental hotspot volcanoes. Answer: Caldera-forming
volcanoes (e.g., Yellowstone).
◉ Hazard. Answer: A natural event that could cause harm (e.g.,
eruption, landslide, lahar).
◉ Risk. Answer: The likelihood that harm will occur to people or
property from a hazard.
◉ Example of a hazard. Answer: Pyroclastic flow from Mount
Rainier.
◉ Example of a risk. Answer: High risk for towns built on old lahar
deposits below the volcano.
