Science 4th Monthly Exam - How Earthquake is Measured Magnitude and Intensity

Earthquake

can be measured by identifying its magnitude and intensity

Magnitude

pertains to the strength and the size of an earthquake

Magnitude

measure of the amount of epicenter using mathematical formulas and information from Seismograms

Magnitude

measured by the open-ended Richter scale

Seismograms

writing produced by an instrument that detect earthquake

Charles Richter

developed Richter Scale

Charles Richter

American Seismologist

Richter Scale

developed by Charles Richter

no upper or lower limits

Scale is open-ended because it has __________

Shallow or little earthquakes

expressed in negative numbers

Stronger

expressed even beyond the highest number on the scale

Intensity

measures the observed effects of an earthquake on people, geologic structures, and manmade structures

Intensity

varies from one location to another

Modified Mercalli Intensity (MMI) Scale

popular and currently used scale which classifies earthquake effects

Guiseppe Mercalli

Italian seismologist, complied the original scale 1902

BEFORE

Know the earthquake hazard in your area.

BEFORE

Follow structural design and engineering practices when constructing a house or building.

BEFORE

Evaluate the structural soundness of the buildings and houses; strengthen or retrofit if necessary.

BEFORE

Strap or bolt heavy furniture’s/cabinet to the wall.

BEFORE

Check the stability of hanging objects like ceiling fans and chandeliers.

BEFORE

Breakable items, harmful chemicals, and flammable materials should be stored properly in the lowermost secured shelves.

DURING

If possible, quickly open the door for exit.

DURING

Duck under a sturdy desk or table, hold on to it, and protect your head with your arms.

DURING

Stay away from glass windows, shelves, cabinets, and other heavy objects.

DURING

Beware of falling objects. Be alert and keep your eyes open.

DURING

Stay away from trees, powerlines, posts, and concrete structures.

DURING

If you’re near the shore and feel an earthquake, especially if it’s too strong, move quickly to higher grounds.

AFTER

Check yourself and others for injuries

AFTER

Check water and electrical lines for damages.

AFTER

Check for spills of chemical, toxic, and flammable materials

AFTER

Check and control fires that may spread

AFTER

Don’t use elevators

AFTER

Don’t enter damaged buildings

AFTER

Don’t use the telephone unless necessary

AFTER

Don’t PANIC

I

not felt except by very few under especially favorable conditions

II

felt only by a few people at rest, especially on upper floors of buildings

III

felt quite noticeably by people indoors, especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of truck. Duration estimated

IV

Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably

V

Felt by nearly everyone; many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocks may stop

VI

Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight

VII

Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken

VIII

Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned

IX

Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations. Liquefaction

X

Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Rails bent.

XI

Few, if any, (masonry) structures remain standing. Bridges destroyed. Broad fissures in ground. Underground pipe lines completely out of service. Earth slumps and land slips in soft ground. Rails bent greatly

XII

Damage total. Waves seen on ground surfaces. Lines of sight and level disorted, Objects thrown upward into the air