6. from each of the stations using the
formula:
Where:
d= Td x 100 km 8
seconds
d = distance (km)
Td = time difference in the
arrival time of P-wave and
S-wave (seconds)
7. 3. Choose one of the recording
stations and measure the
computed distance on the
map scale ( the scale of the
map is 1 cm: 70 km). Set your
compass for that computed
distance.
8. 4. Center your compass on the
station you have chosen. Draw a
circle.
5. Repeat steps 3 and 4 for the
rest of the stations. You should
get three circles that intersect or
nearly intersect at a point. This
intersection is the epicenter.
12. The distance-time graph
shows that S- P interval is
about 10 minutes.
Q3. What is the distance
of the epicenter from
the seismic station?
Q4. What do you think is
the importance of
13. RECORD
-ING
STATION
TIME
DIFFERENCE IN
THE ARRIVAL
TIME OF P-
WAVE AND S-
WAVE
(Seconds)
DISTANCE OF
EPICENTER
FROM THE
STATION (Km)
COMPUTED
DISTANCE ON
THE MAP (Cm)
(1 cm : 70 km)
BATANGAS 44.8 560 8
PUERTO
PRINCESA
32 400 5.7
LET’S CHECK YOUR ANSWERS
14. Let’s check your answers!
Q1. Since the three circles drawn intersect in
the sea near Negros, it is where the
epicenter is.
Q2. Assuming that the two circles will intersect,
the circle will intersect at two points.
Therefore, there will be two locations that
could possibly be the epicenter.
15. Let’s check your answers!
Q3. 9, 000 km
Q4. Locating earthquake epicenters will
pinpoint which fault lines are active.
Usually, the less active fault line stores great
amount of potential energy that could cause
major earthquake once released. Therefore,
places near fault lines that remain inactive for
a long period of time are due to experience a
major earthquake.
18. FILL IN THE BLANKS:
1. According to the plate tectonics model,
the entire lithosphere of the Earth is
broken into numerous segments called
______.
2. Each plate is slowly but continuosly
_____.
3. ______ is formed when plates move
apart, creating zone of tension.
19. FILL IN THE BLANKS:
4. ______ is present when two plates
collide.
5. ______ is characterized by plates that
are sliding past each other.
6. ______ give rise to several geologic
features and events.
7. The thick part of the Earth’s crust, not
located under the ocean.
20. IDENTIFICATION:
8. A vibration of Earth due to the rapid
release of energy
9. A break in a rock along which movement
has occurred
10. Any break in a rock in which no
significant movement has taken place
11. A mass of molten rock formed at depth,
including dissolved gases and crystals
21. IDENTIFICATION:
12. A continuous mass of land with long
width and height on the ocean floor.
13. A theory which suggests that Earth’s
crust is made up of plates that interact
in various ways, thus producing
earthquakes, mountains, volcanoes and
other geologic features.
22. IDENTIFICATION:
14. An event in which a slab of rock thrusts
into the mantle
15. A depression in the seafloor produced
by subduction process
23. MATCHING TYPE: Match column A with B and C
A B C
TYPE OF PLATE
BOUNDARY
RELATIVE MOTION OF
THE PLATES
GEOLOGIC
FEATURES/EVENTS
PRESENT
16. DIVERGENT A. Moving away from
each other
D. Earthquakes
17. CONVERGENT B. Moving towards
each other
E. Mountains,
volcanoes, trenches,
and earthquakes
18. TRANSFORM
FAULT
C. Sliding past each
other
F. Rift Valleys, Oceanic
ridges, and earthquakes
