Science Quiz

Earthquake

a sudden vibration or tremor of Earth’s crust

Focus

place where an earthquake originates; within the crust

Epicenter

location on the surface directly above the focus

tectonic earthquakes

earthquakes caused by tectonic activity and/or plate interactions, releasing seismic wavesEarthquakes

volcanic earthquakes

Earthquakes caused by volcanic activity

Faulting

primary cause of earthquakes

Plate boundaries

where most major earthquake happen

Circum-Pacific Belt/Pacific Ring of Fire

bordered by active tectonic plate boundaries on all sides; many volcanoes are active; 80% of volcanic activity happens here

Seismology

study of earthquakes

Seismograph

used to detect earthquakes

Seismologists

experts on earthquakes

Intensity

measure of strength of an earthquake; indicated by the population and damage

Modified Mercalli Scale

used to indicate an earthquake’s intensity, from I to XII.

Magnitude

amount of energy released by an earthquake

The Richter Scale

measures magnitude; ratings from 1.0 to 9.0 or higher

Foreshocks

small earthquakes that precede a major one

Aftershocks

smaller earthquakes that follow a major one

PHIVOLCS

Philippine Institute of Volcanology and Seismology

PEIS

PHIVOLCS Earthquake Intensity Scale; PHIVOLCS’s standardized quake intensity scale, intensities I to X.

Tsunamis

Or great seismic sea waves, happen when a layer of rocks on the sea of ocean floor slips and moves upward or sideward. Can rise to about 30 meters, crests can reach up to 100 meters; they are very fast

Volcano

vent in the surface of the Earth; gases, hot rock, and lava are ejected.

Crater

funnel-shaped opening of a volcano

Magma

melted rock beneath/within the Earth

Lava

magma that has reached Earth’s surface

Volcanism

one of the major mountain-building forces of Earth

100 C to 650 C

temperature of vapors/steam emitted from volcano eruptions

Gaseous vapors

containing hydrochloric acid, sulfur, and boron, along with carbon dioxide, carbon monoxide, methane, hydrogen, nitrogen, and argon.

Tephra

fragments of rocks and ash

volcanic bombs

larger mass fragments of tephra

lapilli

smaller fragments of tephra

lahar

formed from volcanic material carried down together by rain with streams of mudflow

Types of eruptions

explosive, quiet, intermediate

Explosive eruption

Most violent and destructive, caused by immense pressure in the magma chamber, frequently from cinder cones

Quiet eruption

lava flows out of the crater and moves down the slopes slowly, causing lava cones. Also called “oozing volcanoes”

Intermediate

Has chances of being explosive or quiet

Intensity I

Scarcely perceptible; still water in containers oscillates slowly

Intensity II

Slightly felt; hanging objects slightly swing; still water in containers oscillates noticeably

Intensity III

Weak; felt by many people indoors; water in cont. oscillates moderately; like the passing of a light truck

Intensity IV

Moderately strong; felt by people indoors and some people outside; floors and walls of wood-framed buildings creak

Intensity V

Strong; felt by most people in and outdoors; sleeping people are awakened; strong shaking and rocking

Intensity VI

Very Strong; Frightened; trees are shaken noticeably; wall plaster may crack; motorist feel as if they are driving with flat tires

Intensity VII

Destructive; difficult to stand upstairs; heavy things topple; old structures are damaged considerably

Intensity VIII

Very destructive; difficult to stand anywhere, water splashes over riverbanks, liquefication makes buildings to sink, tilt, or topple; concrete and foundations of bridges destroyed

Intensity IX

Devastating; forcibly thrown to the ground, heavy structures are toppled or broken, landslides and liquefication widespread, boulders are thrown

Intensity X

Completely devastating; practically all human-made structures destroyed, trees are uprooted/broken, ground fissures, change in river courses