Moment and Richter are very similar but most people prefer to use the Richter in today’s world.
January 1- 30,
AWARENESS MONTHAWARENESS MONTH
Earthquake Safety: Don’t be
The Jamaica Fire Brigade being the first respo nder to all
emergencies o n the island, must carry o ut regular training exercise
to mentally and physically prepare the o rganizatio n’ s firefighters to
dealwith any and every emergency that may arise.
The damage that may cause by an Earthquake willundo ubtedly
require all firefighters to have an understanding o f its effect and
ho w to effectively execute a respo nse.
It is also very impo rtant fo r firefighters to kno w ho w to care and
pro tect themselves and victims fro m the apparent hazards cause by
this natural pheno meno n while carrying o ut their duties.
Therefo re, let us no w lo o k at… ..
What is an Earthquake?
An Earthquake(EQ) istheshaking of the
surfaceof theearth resulting from thesudden
releaseof energy in theearth crust that creates
Earthquakecan beviolent enough to toss
peoplearound or so devastating to destroy a
EQ aremeasured using Seismometerand
variousscales. You havethe…
1. Moment Magnitude Scale (MMS)
3. Mercalli Scale
At theearth’ssurface, an EQ manifested itself by
shaking and most timescausedisplacement of the
ground, structural damage, landslideand volcanic
When itsepicenterislocated offshore, it may
trigger a tsunami.
Theword EQ ismostly usein general senseto
describetheshaking of theearth whether its
natural or man-made.
It ismostly causeby theraptureof a
geological faults and generatesseismic waves.
But also by eventssuch asmineblast and
nuclear test (Man-made)
Thisisanatural occurring earthquake. This
happen anywherein theearth wherethereare
sufficient stored energy to fractureafault.
Most faultshaveirregular surfaces. When these
faultspast along each other, thefrictional
resistanceincreaseand lead to aform of stick-slip
behavior or “lock”.
continued leading to increasestressand therefore
strain energy arestorearound thefault surfaces.
Thiscontinued until thestresshasrisen
sufficiently to break from itsstick-slip
behavior, suddenly allowing sliding over the
“lock” portion of thefaultsand releasing the
Thisenergy releasecausesseismic waves,
frictional heat at thefaultssurfaceand
cracking of theearth (rock) thuscausing an
Therearethree(3) main typesof faults
Normal and Reverseare
Normal and Reverse(Thrust) faulting isthe
displacement of thefaultsin thedirection of a
dip and movement on them carried avertical
Normal faultsoccur in area
extension creating a
Reverse(Thrust) fault occursin areawherethe
crust areshorten. Thesearethemost powerful
earthquakes. TheseEQ aremagnitude7 and
Strike-Slip fault aresteep structurewherethey
slidepasseach other horizontally.
A fault movement of both Dip-Slip and Strike-
Slip isknown as….
Theeffectsof EQ includebut arenot
limited to thefollowing
• Damageelectrical line
• Damagewater main
• Saturated soil become
• Building collapse
• Other structuresink
NB: A majorhazard
carrying out rescue
• Largevolumeof water
• Long and destructive
• Travel at an average350
• Water exceeding its
• Overflow of water reaching
This is as a result of an
earthquake damaging a
• Lossof lifeor injuries
• Property damage
• Lack of basic necessity
• Mental consequences
(depression, anxiety, panic)
Lisbon, Portugal in 1755
Hit by an EARTHQUAKE causing aTsunami, Fires, Collapse
Buildingsand Lossof Lives
• Seismic Wave – wavesof energy that travel
• Mo ment Magnitude Scale (MMS) –
Measurement of an earthquakeby theamount
of energy release.
• Richter MagnitudeScale– assigned a
magnitudenumber to quantify theenergy
releaseby an earthquake.
• Mercalli Scale – measuretheintensity and
effect of an earthquakeon theearth surface
• Epicentre – thepoint on theearth’ssurface
that isdirectly abovethehypocentreor focus
• Hypo cetre – originated point of an earthquake,
wherethefirst strain energy release.
• Fault – planar fracture(discontinuity in a
volumeof rock. Significant displacement of
• Seismometer – aunit that measurethemotion
of theground generated by and earthquake.