Locating earthquake by using Triangulation Method with the description of Earthquake, Body Waves, Epicenter, Focus, Seismogram, Seismograph , P and S waves Time travel Curve and Graph and scaling

1. PRESENTATIONON HOWTO LOCATE EPICENTEROF AN
EARTHQUAKE
Presenting To
Md Ismile Hossain
Lecturer ( Geology and Geomorphology)
Department of Civil Engineering
UNIVERSITY OF CREATIVE TECHNOLOGY
CHITTAGONG
Presented by
Md Kizased – 200212044
Md Zamil Uddin- 200212050
Md Ahsan Ullah- 200212047
Md Muktasir Alam-200212051
Mohammad Naimul Hossain- 200212046

2. WHAT IS EARTHQUAKE
• The shaking or trembling
caused by the sudden release
of energy
• Usually associated with
faulting or breaking of rocks
• Continuing adjustment of
position results in
A Snap after San Francisco Earthquake -1906

3. THE FOCUS AND EPICENTER OF AN EARTHQUAKE
• The point within Earth where
faulting begins is the focus.
• The point directly above the
focus on the surface is the
epicenter

4. TRIANGULATION METHOD
• Triangulation A
mathematical method
for locating the
epicenter of an
earthquake using three
or more data sets from
seismic stations. This
data is collected using
seismographs.

5. SEISMOGRAPHS AND SEISMOGRAM
• A seismogram is a visual record that is created by a seismograph.
• A seismograph is a piece of equipment that records earthquake
movements.

6. CHARACTERISTICS OF P WAVES AND S
WAVES
P or primary waves
fastest waves
travel through solids, liquids, or gases
compressional wave, material
movement is in the same direction as
wave movement
S or secondary waves
slower than P waves
travel through solids only
shear waves - move material
perpendicular to wave movement

7. EARTHQUAKE’S P AND S WAVES TIME TRAVEL
GRAPH
• A travel-time curve is
a graph of the time
that it takes for
seismic waves to
travel from the
epicenter of an
earthquake (time and
distance = zero)
to seismograph
stations varying
distances away

8. LOCATING EPICENTER OF AN EARTHQUAKE
COLLECTING DATA FROM SEISMOGRAM
FOR 3 STATION

9. USING THE DATA FROM THE RECORDING STATIONS:
• Station A: San Francisco, California
P-Wave arrival 3:02:20 S-Wave arrival
3:06:30 What is the time
difference
between P and S
wave arrivals?

10. USE THE DATA FROM THE RECORDING STATIONS:
• Station B: Denver, Colorado
P-Wave arrival 3:01:40 S-Wave arrival
3:05:00
What is the time
difference
between P and S
wave arrivals?

11. USE THE DATA FROM THE RECORDING STATIONS:
• Station C: Missoula, Montana
P-Wave arrival 3:01:00 S-Wave arrival
3:03:00
What is the time
difference
between P and S
wave arrivals?

12. TAKE A PIECE OF PAPER, AND MARK
OFF THE DIFFERENCE IN ARRIVAL TIME
4:10
METHOD OF FINDING DISTANCE

13.  MOVE THE PAPER UNTIL
THE TWO TICK MARKS
LINE UP WITH THE P
AND S CURVES
 WHEN TI CK MARKS LINE
UP
, GO STRAIGHT DOWN
AND READ THE
EPICENTER DISTANCE
EPICENTER DISTANCE
OF 2800 KM
METHOD OF FINDING DISTANCE

14. EPICENTER DISTANCES
San Francisco: 4:10=
Denver, Colorado: 3:20=
Missoula, Montana 2:00=
2,800km
1100km
2,000km

15. LOCATING EPICENTER
Using the map scale, and a
drafting compass we set it to the
appropriate length for the
distance from the first location to
the epicenter. Place the compass
point at this location and draw
an arc using the distance as the
radius. Repeat for the other two
locations. The intersection of the
three arcs identifies the epicenter
of the earthquake.
San Francisco: 4:10 2,800km
1,000
2,000
3,000
4,000
5,000
Open compass to the
EXACT distance on the
scale.

16. . .
.
Have to use carefully set
compass to draw a circle
around each seismic
station.
we've found
a possible epicenter!
LOCATING EPICENTER