Earthquake Hazards

and Safety

An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release

of energy in the Earth's crust that creates seismic waves. The seismicity or seismic

activity of an area refers to the frequency, type and size of earthquakes experienced over a

period of time. Earthquakes are measured using observations from seismometers

The Earth

Know Your ZOne

Earthquake Zones in World Map

Interior Structure of Earth

CRUST (0-100 KM )

MANTLE (100-2900 KM )

The Earth's outermost surface is called the crust. The crust is relatively light and brittle.

Most earthquakes occur within the crust. Scientists believe that below the lithosphere is a

relatively narrow, mobile zone in the mantle called the asthenosphere (from asthenes,

Greek for weak).

The region just below the crust and extending all the way down to the Earth's core is called the

mantle. The mantle, a dense, hot layer of semisolid rock.

Core (100-2900 KM )

Beneath the mantle is the Earth's core. The Earth's core consists of a fluid outer core

and a solid inner core.

Inner Core (2900-5100 Km) Outer Core (5100 -6378 Km)

Focus and Epicenter of Earthquake

What Causes Earthquake?

The sudden slip at the fault causes the earthquake…….a violent shaking of the Earth

when large elastic strain energy released spreads out through seismic waves

that travel through the body and along the surface of the Earth.

Fault

Earthquakes occur on faults. A fault is a thin zone of crushed rock between two blocks of rock,

and can be any length, from centimeters to thousands of kilometers.

When an earthquake occurs on one of these faults, the rock on one side of the fault slips

with respect to the other. The fault surface can be vertical, horizontal, or at some angle to the

surface of the earth. The slip direction can also be at any angle. We classify these into two basic

cases: strikeslip and dip-slip motion.

General Characteristics

Earthquake Vibration

Earthquake vibrations occur in a variety of frequencies and velocities. The actual rupture

process may last from a few seconds to as long as one minute for a major earthquake.

Seismic waves generated by the rupture can last from several seconds to a few minutes.

Ground shaking is caused by body waves and surface waves

Depth of Earhquake

Deep (300-700 Km)

Intermediate (300-60 Km)

Shallow (60-0 Km)

Measurement Scale

Magnitude- Richter (Charles Richter) Measures

the magnitude of the

Intensity , degree of damage (Mercilli)

Determining the magnitude of an earthquakeMagnitude -- measure of energy released during earthquake. There are several different ways to measure magnitude. Most common magnitude measure is Richter Magnitude, named for the

renowned seismologist, Charles Richter.

Richter Magnitude• Measure amplitude of largest S wave on seismograph record. • Take into account distance between seismograph & epicenter.

Richter Scale• Logarithmic numerical (NOT a physical) scale• Increasing one whole unit on Richter Scale represents 10 times greater

magnitude. • Going up one whole unit on Richter Scale represents about a 30 times

greater release of energy.

Intensity • Intensity refers to the amount of damage done in an earthquake• Mercalli Scale is used to express damage

Family Readiness

•Create a family Earthquake plan

•Know the safe spot in each room

•Know the danger spots

•Decide where your family will reunite if separated

•Keep a list of emergency phone numbers

•Develop a survival kit for work, car, and home

Hazards associated with Quakes• Shaking:

Frequency of shaking differs for different seismic waves. High frequency body waves shake low buildings more. Low frequency surface waves shake high buildings more. Intensity of shaking also depends on type of subsurface material. Unconsolidated materials amplify shaking more than rocks do. Fine-grained, sensitive materials can lose strength when shaken. They lose strength by liquefaction. Buildings respond differently to shaking depending on construction styles, materials Wood -- more flexible, holds up well Earthen materials -- very vulnerable to shaking.

• Ground displacement:Ground surface may shift during an earthquake (esp. if focus is shallow). Vertical displacements of surface produce fault scarps.

• Tsunamis (NOT tidal waves)Tsunamis are huge waves generated by earthquakes undersea or below coastal areas. If earthquake displaces sea surface, wave is generated that can grow as it moves over sea surface.

• FiresUsually occurs from shifting of subsurface utilities (gas lines)

Home Preparedness

•Learn how to shut off gas,

water, and electricity

•Check chimneys, roofs, and

wall foundations for stability

•Secure heavy furnishings

•Secure water heater and

appliances

•Keep heavy objects on lower

shelves

•Maintain emergency food,

water, medicine, first aid kit,

tools, and clothing

Emergency Supplies

•First Aid supplies

Band-Aids

antibiotic ointment

latex gloves

cold/hot packs

ace bandages

arm sling

Tylenol or Advil

diarrhea medication•Equipment

work gloves

shovel

tents

sleeping bags

ready to eat foods

clothing

radio, flashlights

CASH

Emergency Food

•Camp or backpacking stove

propane tank

•Canned foods

manual can opener

•MRE’s

•Granola bars

•Energy bars

Safe Drinking Water

•Store a supply of water

1 and 5 gallon containers

do not store on concrete•Purifying tap water

8 drops bleach per gal of water

add bleach when storing

or, boil for 10 minutes•Water from water heater

turn off gas or electric

turn off cold water supply

once cooled, drain at bottom•Other sources

toilet storage tank

melted ice cubes

water trapped in pipes

During an Earthquake

•Stay away from windows, bookcases, file cabinets, heavy mirrors, and

other heavy objects that could fall

•Duck under a desk or sturdy table

•Watch for falling plaster or ceiling tiles

•Stay undercover until the shaking stops, and hold onto your cover

•If the desk or table you are under moves… move with it

•If in your car, stop, but

not on a bridge, or under

trees or a power line

•If outside, stay outside,

and move to an area

clear of overhead trees,

power lines, or objects

that could fall from a

structure

•Don’t forget about

aftershocks

After The Earthquake

•Be prepared for aftershocks, plan for cover when they occur

•Check for injuries, give first aid as necessary

•Remain calm, try to reassure others

•Wear shoes to avoid injury from broken glass

•Check for fire and take appropriate actions

•Check gas, water, and electric lines

•Tune to emergency broadcast system on radio

How to Shut Off Utilities

Gas Shutoff

Water Shutoff

Electricity Shutoff

Thanks to:

All My Friends

for being a part