SCI | QUARTER 4

Fissure

elongated fracture or crack on Earth’s crust from which lava erupts

Conduit

passageway through which magma travels to reach Earth’s surface

Vent

opening where volcanic materials are released

Crater

bowl-shaped depression at the top of the volcano where the vent is located

Flank

side of the volcano

Magma chamber or reservoir

underground compartment where the magma is stored

STRATOVOLCANO (COMPOSITE CONE VOLCANO)

The most dangerous volcanoes

SHIELD VOLCANO

Formed by loose and fluid lava that flows over each other. The magma of a shield volcano contains lower amounts of dissolved gases and silica

CINDER CONE

Volcanic eruptions are short-lived and appear like a wild fountain show of fiery lava spewed high in the air

Caldera complex

is a depression formed at the summit of shield volcanoes.

Lava dome

mounds of lava formed after a volcanic eruption.

Submarine volcanoes

these are volcanoes on the ocean floor and are formed through collision of oceanic plates

Glacial volcanoes

are volcanoes that are overlain by glaciers. Examples include the Alaskan volcano.

Blasts

these are hot bursts of trapped gases that push their way through solid barriers and rapidly into the atmosphere

Dome growth

this refers to a mound of lava that grows inside the crater, called a cryptodome. If it grows outside the volcano, it is called an exodome

Gases

water vapor, hydrogen sulfide, sulfur dioxide, hydrogen chloride, hydrogen fluoride, hydrogen and carbon dioxide. Other gases include nitrogen, methane, argon, and helium

Lahar

also called as mudflow or flow of volcanic debris. Can be classified as primary (from the eruption) and secondary (because of heavy rainfall)

Lava flow

refers to the molten rocks that move down the slope of volcanic vents. The viscosity of the lava and the steepness of the volcano slope can influence the rate of lava flow

Pyroclastic flow

this refers to glowing hot material that moves down the slope of an erupting volcano and comes in contact with the surface. Pyro (fire) and clast (broken) are rock fragments spewed during volcanic eruptions

Pyroclastic surges

these are volcanic materials of gases, ash, rock fragments, and water extruded above the ground

Tephra falls

these may consist of combinations of pumice, scoria (basalt), thick rock fragments and crystals with tephra particles

Tsunami

are series of sea waves caused by displacement of large volumes of water because of an underwater earthquake or volcanic eruption

Ash plume

the cloud of ash that comes out of the crater and can travel not just to nearby communities but also to nearby countries

HAWAIIAN

is the least violent type, with highly fluid or runny lava flowing out several vents.

STROMBOLIAN

is violent, featuring continuous ejection of magma and gas.

VULCANIAN

a thick, viscous magma flows around the vent as solid lava and dust are ejected.

PLINIAN

the most violent and explosive type of eruption which is caused by the buildup of viscous magma and dissolved gas.

Geology

is a branch of Science that deals with the study of the physical and historical aspects of Earth.

Geochemistry

chemical composition and changes of materials that make up Earth

Geophysics

behavior of Earth in response to physical forces

Mineralogy

chemical composition and structure of minerals

Petrology

composition and origin of rocks

Paleontology

fossils or remains of organisms

Paleography

geologic maps and location of land masses that may have been lost

Stratigraphy

layers of Earth’s bedrock, which is essentially that of soil, sand, pebbles, stones and rocks

CRUST

the solid rock layer that makes up the outermost portion of the Earth.

MANTLE

below the crust which stretches to a depth of about 2890 km before reaching the core.

CORE

the outer core extends 2266 km while the inner core is 1220 km thick and more than 6200 km below the Earth’s layers.

Tectonic plates:

continental and oceanic

Continental plates

thicker, lighter, and are made up of granitic rocks

Oceanic plates

dense and are made up of basaltic rocks

Convergent boundaries

tectonic plates move against or toward each other.

Oceanic-continental convergence

an oceanic crust may be consumed and brought down through subduction below the continental plate.

Oceanic-oceanic convergence

one oceanic crust is subducted under another oceanic crust to form deep ocean trenches.

Continental-continental convergence

no subduction occurs.

Divergent boundaries

tectonic plates move away from each other.

Transform boundaries

tectonic plates slide horizontally past each other and form faults.

IGNEOUS

are rocks formed out if magma that has cooled down.

SEDIMENTARY

are rocks that consist of previously loose materials, such as sand and soil, which have settled down and are compacted by the weight of overlying sediments and water to make them solid.

METAMORPHIC

are rocks formed when sedimentary rocks or igneous rocks are subjected to enough heat and pressure to change their mineralogical and chemical characteristics

Panning

for gold in a river or a stream is a form of mining.

Smelting

uses heat and chemical agents to chemically separate the desired metal from the other components of the ore

Gold

most valuable metal in the Philippines.

Philippine jade

is not of common variety.

Coal

form of fossil fuel, which refers to organic materials (remains of plants and animals) that have experienced physical and chemical transformations over a long period of time.

Mine tailings

materials that remain after extraction of ore minerals