January 1- 30, 2016

EARTHQUAKE EARTHQUAKE AWARENESS MONTHAWARENESS MONTH

Earthquake Safety: Don’t be scared…..be prepared

District Officer Dervan DawesSuppressionWestmoreland Division Jamaica Fire Brigade

PrefaceThe Jamaica Fire Brigade being the first responder to all emergencies on the island, must carry out regular training exercise to mentally and physically prepare the organization’s firefighters to deal with any and every emergency that may arise.

The damage that may cause by an Earthquake will undoubtedly require all firefighters to have an understanding of its effect and how to effectively execute a response.

It is also very important for firefighters to know how to care and protect themselves and victims from the apparent hazards cause by this natural phenomenon while carrying out their duties.

Therefore, let us now look at…..

What is an Earthquake?An Earthquake (EQ) is the shaking of the surface of the earth resulting from the sudden release of energy in the earth crust that creates seismic waves

Earthquake can be violent enough to toss people around or so devastating to destroy a whole city.

EQ are measured using Seismometer and various scales. You have the…

1. Moment Magnitude Scale (MMS)2. Richter Scale3. Mercalli Scale

At the earth’s surface, an EQ manifested itself by shaking and most times cause displacement of the ground, structural damage, landslide and volcanic activity.When its epicenter is located offshore, it may trigger a tsunami.

The word EQ is mostly use in general sense to describe the shaking of the earth whether its natural or man-made.

It is mostly cause by the rapture of a geological faults and generates seismic waves. (Natural)

But also by events such as mine blast and nuclear test (Man-made)

Tectonic EarthquakeThis is a natural occurring earthquake. This happen anywhere in the earth where there are sufficient stored energy to fracture a fault.

Most faults have irregular surfaces. When these faults past along each other, the frictional resistance increase and lead to a form of stick-slip behavior or “lock”. Once the faults are “lock”, relative motion continued leading to increase stress and therefore strain energy are store around the fault surfaces.

This continued until the stress has risen sufficiently to break from its stick-slip behavior, suddenly allowing sliding over the “lock” portion of the faults and releasing the stored energy.

This energy release causes seismic waves, frictional heat at the faults surface and cracking of the earth (rock) thus causing an earthquake.

Earthquake FaultsThere are three (3) main types of faults

1. Normal2. Reverse (Thrust)3. Strike-Slip

Normal and Reverse aredip-slip.

Normal and Reverse (Thrust) faulting is the displacement of the faults in the direction of a dip and movement on them carried a vertical component.

Normal faults occur in area when there is a crust

extension creating a divergent boundary.

Reverse (Thrust) fault occurs in area where the crust are shorten. These are the most powerful earthquakes. These EQ are magnitude 7 and above.

Strike-Slip fault are steep structure where they slide pass each other horizontally.

A fault movement of both Dip-Slip and Strike-Slip is known as….

OBLIQUE SLIP

Earthquake Effects

The effects of EQ include but are not limited to the

following

Fire

• Damage electrical line

• Damage gas pipeline

• Damage water main

Soil Liquefaction

• Saturated soil become liquefied

• Building collapse

• Bridges tilt

• Other structure sink

Landslide and Avalanche

• Slope instability

NB: A major hazard to firefighter when carrying out rescue operation

Tsunami

• Large volume of water displacement

• Long and destructive waves

• Travel at an average 350 mile per hour

Flooding

• Water exceeding its formation capacity

• Overflow of water reaching land

This is as a result of an earthquake

damaging a dam

Human Impact

• Loss of life or injuries

• Property damage

• Disease

• Lack of basic necessity

• Mental consequences (depression, anxiety, panic)

Lisbon, Portugal in 1755

Hit by an EARTHQUAKE causing a Tsunami, Fires, Collapse Buildings and Loss of Lives

Glossary• Seismic Wave – waves of energy that

travel through Earth’s layers

• Moment Magnitude Scale (MMS) – Measurement of an earthquake by the amount of energy release.

• Richter Magnitude Scale – assigned a magnitude number to quantify the energy release by an earthquake.

Glossary• Mercalli Scale – measure the intensity and

effect of an earthquake on the earth surface

• Epicentre – the point on the earth’s surface that is directly above the hypocentre or focus

• Hypocetre – originated point of an earthquake, where the first strain energy release.

Glossary• Fault – planar fracture (discontinuity

in a volume of rock. Significant displacement of rock mass movement)

• Seismometer – a unit that measure the motion of the ground generated by and earthquake.

Next Topic

THANK YOU

Preparedness And

Protection