science volcano

A’a

The type of lava that hurts. Forms with rapid lava flow

Hornito

A small spatter cone that forms on the surface of a lava flow (usually pahoehoe).

Mafic

low silica, high magnesium and iron, dark color

Sill

A sheet of igneous rock intruded between and parallel with the existing strata.

Andesitic magma

higher viscosity and lots of dissolved gas, so it tends to erupt explosively

Igneous rock

Formed from Magma or Lava

Magma

is made up of solid, liquid, and gas and it is underground

Skylight

an opening in the roof of a lava tube

Ash

More deadly than lava or gas. Increases albedo of the atmosphere. a pyroclastic that is less than 2mm in diameter. Also comes out of volcano.

Intermediate

In-between felsic and mafic.

Magma Chamber

The underground space usually deep below the earth's surface occupied by magma that may ascend from it to or toward the surface

Stock

The same thing as a Batholith but smaller. Under 100 square km.

Basaltic magma

A lower viscosity and less dissolved gas trapped in it, so it tends to erupt gently

Intrusive  (Plutonic)

They cool slowly so they have these textures: Coarse-grained and very coarse grained. (yellow)

Pahoehoe

is lava that has a smooth (yet often wrinkled) surface.

Stratovolcano  (Composite Volcano)

Formed at convergent subduction boundaries. Classic volcano shape. Famous ones:Mt. Helen. Lots of them are located on the ring of fire.

Batholith

Over 100 km squares.

Kipuka

a small piece of land completely surrounded by lava flows

Pele

the Hawaiian goddess of volcanoes.

Texture

The environment of the rocks forming affects texture.

Caldera

Large depressions are caused by the collapse of the ground above an emptied magma chamber. Formed on continental hotspots.

Laccolithic

looks like mushroom top. Above a dike.

Pele’s Hair

Is a naturally-spun volcanic glass that is blown away from lava fountains, cascading lava falls, or turbulent lava flows.

Tsunami

a Japanese word with the English translation, "harbor wave.” (Btw that person is dead)

Cinder Cone Volcano

The “anthills” of the volcano world. Steep slopes and abnormally large crater.

Lahar

a rapidly flowing mixture of rock debris and water that originates on the slopes of a volcano. A mudslide.

Pele’s Tears

Small bits of molten lava in fountains can cool quickly and solidify into glass particles shaped like spheres or tear drops.

Volcanic Explosivity Index (VEI)

Measures the amount of ash and debris thrown into the atmosphere during eruptions. If it has a high VEI then it can change climate for years.

Crystallization

The process of forming crystals in magma.

Lava Block

is a pyroclastic larger than 64 mm Comes from parts of volcanic cone getting blasted in air

Pyroclastic Flow

fragments of volcanic rock and lava blasted into the air by a volcanic eruption

Volcanic fissure

Happened at Heimaey, Iceland, huge crack that spews lava.

Dike

an intrusion of igneous rock cutting across existing strata.

Lava Bomb

a large pyroclastic that is still molten as it flies

Rhyolitic magma

felsic magma with very high silica content.

Volcanic Neck

vertical structure left exposed once the outside of the volcano weathers and erodes away

Discordant

Plutons cut across layers of surrounding rock. Batholiths and dikes are examples of discordant rock bodies. A discordant igneous rock body cuts across the pre-exiting rock bed

Lava Lake

Large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression.

Rift Eruption (Curtain of Fire)

divergent volcanism on land.

Volcanic Pipe

solid lava conduit from magma chamber to surface

Extrusive (Volcanic)

They are above the surface, cool quickly. Textures are: Glassy, Vesicular, and fine grained.

Lava

principal hazard from a volcano, moves slowly typically and can burn you.

Clinkers

jagged surface composed of broken lava blocks

Lapilli

Latin for “little stone,” and is a pyroclastic that is between 2mm and 64mm (a tennis ball) in diameter. Least deadly.

Pillow Basalt

Underwater divergent volcanism creates this.

Vesicular

gassy and filled with air holes like pumice.

Coarse-grained

With large crystals like granite.

Pluton

Igneous rock formations that cool and solidify below the surface.

Viscosity

measures a liquid’s resistance to flow. High Viscosity=thicker and low is thinner.

Lava Bench

Lava that is moving down the side of a place that makes its way to the shoreline and it makes more area to the island. Very Unstable

Pyroclastics (Tephra)

the layers that make up a stratovolcano.

Lava Mold

cylindrical hollows left behind in a lava flow if the lava has completely incinerated the tree it once flowed around

Ring of Fire

Region surrounding the Pacific plate where an increased amount of volcanism takes place due to subduction. Lots of Stratovolcanoes.

Volcanism

refers to the activity of magma forming and coming toward the surface.

Felsic

high silica, light color

Lava Tree

formations created when pahoehoe flows around a tree and cools to form a crust around the trunk.

Shield Volcano

volcanoes that are made on oceanic hotspots. Very wide and very tall. Made from lava flowing and piling onto itself. Most famous shield volcano is Mauna Loa.

Volcano

the landform created when magma reaches the surface through an opening in Earth’s crust.

Fine-grained

A texture of extrusive rocks. Rhyolite.

Lava Tube

a natural conduit through which lava travels beneath the surface of a lava flow.

Silica

The more silica something has the more viscosity it has. Felsic has the highest silica content.

Xenolith (Inclusion)

solid rocks picked up on the way out from magma.

Glassy

a texture of extrusive rocks. Obsidian.