- An earthquake's hypocenter or focus is the exact point where seismic energy is released underground, usually between 0-700 km deep. Shallower earthquakes cause more damage since their energy reaches the surface sooner. - Seismic waves radiate outward from the focus in all directions. The point directly above the focus on the earth's surface experiences the strongest shaking and is called the epicenter. - Earthquake magnitude is measured using the Richter scale and indicates the total energy released, while intensity scales like the Mercalli scale describe the effects on people and structures. Proper preparation and safety procedures can help minimize risks from earthquakes.

4. Earthquake focus or
hypocenter
- It is the exact point
inside the crust where
a tremendous amount
of energy actually
start to be released.

5. - It is where the
vibrating waves
originate which travel
outward in all direction.
- Foci (plural for focus)
are found in various
depth underground.

6. • Shallow-focus
earthquake or crustal
earthquake- occur
between 0-70 km
below.
• Intermediate focus-
70-300 km below.

7. • Deep-focus
earthquake or intra-
plate earthquakes
are 300-700 km
deep.

8. • Shallow earthquakes
are usually of large-
spread, resulting to
more damages and
because their foci are
nearer the surface of
the earth.

9. • The energy released
from the foci travel in
all directions until
they reach the
surface of the earth,
causing vibrations.

10. • Epicenter is the point
on the earth’s
surface that is
vertically above the
focus and where
energy waves are felt
most strongly.

11. • Epicenter comes
from the Latin word
epicentrum, which
means “situated at
the centeer”.
• 1st sudden
movement of the
ground is felt.

14. • The energy released
during an earthquake
is in the form of
seismic waves
radiating in all
directions within the
Earth’s crust.

15. • The energy released
during an earthquake
is in the form of
seismic waves
radiating in all
directions within the
Earth’s crust.

18. • Earthquake can be
measured using a
seismograph.
• Seismologist use
seismograph to
detect and record
vibration.

19. • The first seismograph
was invented by a
Chinese astronomer
and mathematician,
Cheng Heng, and he
called it “earthquake
weathercock”

20. • The first modern
seismograph was
invented by an
English seismologist,
John Milne.

23. • Magnitude or the
total amount of
energy released – is
to determine how
destructive an
earthquake was.

24. • Magnitude can be
measured by means
of Richter Magnitude
scale.
• Scale can be
expressed in
numerical value.

25. • Scale was developed
in 1935 by an
American
seismologist, Charles
Ritcher and his
friend, Beno
Gutenberg.

26. • The greater the
amplitude of the
waves, the higher
the magnitude of the
an earthquake, and
the greater severity.

28. • Intensity is the
energy released to
the epicenter to the
ground and the
effects are felt over a
much larger area.

29. • Intensity of an
earthquake can be
determined by how
much damaged has
occurred and the
amount of shaking
experience by the
people.

30. • Intensity is
measured with the
Modified Mercalli
Scale which was
revised by an Italian
volcanologist
Guiseppe Mercalli.

31. • The ratings are
expressed in Roman
Numerals ranging
from I (no damage)
to XII (greatest
destruction)

34. • Earthquake also happen
in bodies of water.
• Tsunami is commonly
called seismic waves
which mislead the
people who thought
that only earthquake
can cause it.

35. • Tsunami are also
caused by undersea
volcanic eruption,
underwater
landslides, glaciers
collapse, land
slumping to the
ocean, meteorites.

37. • It is also incorrect to
call it tidal waves
because tsunamis
are not caused by
tides and unrelated
to the tides.

38. • Tsunami comprises
two Japanese words-
“tsu” (meaning
harbor) and “nami”
(meaning waves)

39. • The most prevalent
cause of tsunami is
the undersea
earthquake.

40. • A tsunami happens
when underwater
earthquakes result in
sudden vertical
deformation of the
seafloor.

42. • It creates a sudden
rise or fall of the
crust under or near
the ocean that
produces vertical
displacement of the
seafloor, displace the
water abover.

43. • Vertical displacement
of the seafloor are
triggered by thrust,
reverse, and normal
faulting where
compression pushes
the rocks.

44. • Vertical deformation
of the seafloor can
generate tsunami.
• Most damaging
tsunami occur near
the Pacific Ocean and
Indian ocean.

47. • For centuries
seismologist could
not use any devices
that can predict the
earthquakes.
• Chinese believe in
what they observe
among their animals.

49. • Examine every part
of the house- know
the safe spots such
as against the wall,
under the table or
desk, and the danger
spots.

50. • Repair any deep
cracks in ceiling or
walls, and defective
electric wirings.
• Bolt or fix heavy
cabinets or furniture
to the wall.

51. • Have a regular
inspection of the
stability oh hanging
objects like frames,
mirrors, ceiling fan
and chandeliers.

52. • Easy-to-break
objects made of
ceramics and glasses
should be kept or
placed in the
lowermost secured
shelves or cabinets.

53. • Keep the dangerous
chemicals such as
cleaning products,
pest sprays, and
flammable materials
or liquids outside the
house.

54. • Turn off the gas
tanks when not in
use.
• Learn and practice
first aid and CPR.
• Always recharge the
cell phones if it is
needed.

55. • Participate in
earthquake drills and
orient the family
about it.
• Unplug the appliance
if not in use.

56. • If possible, make fire
extinguisher
available and put it in
a safe place.
• Be familiar with the
doorways and the
emergency exits.

57. • Prepare a bag filled
with emergency
supplies, important
documents, and
basic needs. Put the
emergency bag
where it can be seen
easily.

59. If indoors:
• Stay inside, be calm
and do the “Drop,
Cover, and Hold”
• Duck under a strong
table or desk and
hold on to it or cover
your head.

60. • Stay away where there
are glass windows,
shelves, cabinets, and
other heavy objects.
• Be alert and keep your
eyes open to be aware
of the falling objects.

61. • Do not stand in
doorways
• Do not use elevators.

62. If Outdoors
• Move to an open
area away from
trees, walls or
concrete structures,
power lines, or tall
buildings.

63. • If driving, do not
attempt to cross
bridges, overpasses
or flyovers.

65. • Keep calm and
expect after shocks,
so be alert. Get out
of the building as
fast as possible.
• Don not use
elevators.

66. • Check yourself and
others for injuries,
apply first aid if
necessary, and do
not touch the
seriously injured
individual.

67. • Do not operate
electrical switches.
• Check the electrical
and water lines for
damage, the
chemicals or toxic and
flammable liquids, and
gas leaks.

68. • Turn on the radio and
listen to the news.
• Use the phone only
in case of emergency
because the disaster
prevention
authorities may need
line connections.

69. • Avoid driving to clear
the streets for
emergency vehicles.
• If you are not
seriously harmed,
look around you to
help others as well
as your neighbors.

70. • If you leave your
home, bring the
emergency kit and
leave a note to let
your family know of
your whereabouts.