Sri Lanka Earthquake

1
Sri Lanka Earthquake Tsunami Warning Training
Program
Session IV.3 Review of the Seismology component
of the training course April 6, 2006 Sri Lanka
2
Sri Lanka Earthquake Tsunami Warning Training
Program

• Key topics covered in the seismology component of
  the course
• Global distribution and frequency of earthquakes.
• Elastic rebound theory.
• The particle motion and path through the Earth of
  major seismic phases (P, S, Surface waves).
• Identification of P, S and surface wave arrivals
  on a seismogram.
• Earthquake magnitude scales.
• The principles of hypocentral location.
• Focal mechanisms.
• Recording station operations and seismic networks

3
Sri Lanka Earthquake Tsunami Warning Training
Program
Handout pages 63, 75-80
4

Sri Lanka Earthquake Tsunami Warning Training
Program

• Frequency distribution of earthquakes

Number of Earthquakes Worldwide for 2000 - 2006 Located by the US Geological Survey National Earthquake Information Center Number of Earthquakes Worldwide for 2000 - 2006 Located by the US Geological Survey National Earthquake Information Center Number of Earthquakes Worldwide for 2000 - 2006 Located by the US Geological Survey National Earthquake Information Center Number of Earthquakes Worldwide for 2000 - 2006 Located by the US Geological Survey National Earthquake Information Center Number of Earthquakes Worldwide for 2000 - 2006 Located by the US Geological Survey National Earthquake Information Center Number of Earthquakes Worldwide for 2000 - 2006 Located by the US Geological Survey National Earthquake Information Center Number of Earthquakes Worldwide for 2000 - 2006 Located by the US Geological Survey National Earthquake Information Center Number of Earthquakes Worldwide for 2000 - 2006 Located by the US Geological Survey National Earthquake Information Center
Magnitude 2000 2001 2002 2003 2004 2005 2006
8.0 to 9.9 1 1 0 1 2 1 0
7.0 to 7.9 14 15 13 14 14 10 4
6.0 to 6.9 158 126 130 140 141 150 21
5.0 to 5.9 1345 1243 1218 1203 1515 1720 239
Log N a - bM
Handout pages 101-114
5
Sri Lanka Earthquake Tsunami Warning Training
Program

• Key topics covered in the seismology component of
  the course
• Global distribution and frequency of earthquakes.
• Elastic rebound theory.
• The particle motion and path through the Earth of
  major seismic phases (P, S, Surface waves).
• Identification of P, S and surface wave arrivals
  on a seismogram.
• Earthquake magnitude scales.
• The principles of hypocentral location.
• Focal mechanisms.
• Recording station operations and seismic networks

6
Sri Lanka Earthquake Tsunami Warning Training
Program
Elastic Rebound Theory Handout pages 62, 95
7
Sri Lanka Earthquake Tsunami Warning Training
Program

• Key topics covered in the seismology component of
  the course
• Global distribution and frequency of earthquakes.
• Elastic rebound theory.
• The particle motion and path through the Earth of
  major seismic phases (P, S, Surface waves).
• Identification of P, S and surface wave arrivals
  on a seismogram.
• Earthquake magnitude scales.
• The principles of hypocentral location.
• Focal mechanisms.
• Recording station operations and seismic networks

8
Sri Lanka Earthquake Tsunami Warning Training
Program
Handout pages 48-60, 72
9
P waves
10
Sri Lanka Earthquake Tsunami Warning Training
Program
Ray paths
Handout pages 82-94
. Whole Earth Geophysics by Robert J. Lillie
11
Sri Lanka Earthquake Tsunami Warning Training
Program

• Key topics covered in the seismology component of
  the course
• Global distribution and frequency of earthquakes.
• Elastic rebound theory.
• The particle motion and path through the Earth of
  major seismic phases (P, S, Surface waves).
• Identification of P, S and surface wave arrivals
  on a seismogram.
• Earthquake magnitude scales.
• The principles of hypocentral location.
• Focal mechanisms.
• Recording station operations and seismic networks

12
Sri Lanka Earthquake Tsunami Warning Training
Program
P
S
vertical
Rayleigh Waves
radial
transverse
Love Waves
Handout page 70
13
Sri Lanka Earthquake Tsunami Warning Training
Program

• Key topics covered in the seismology component of
  the course
• Global distribution and frequency of earthquakes.
• Elastic rebound theory.
• The particle motion and path through the Earth of
  major seismic phases (P, S, Surface waves).
• Identification of P, S and surface wave arrivals
  on a seismogram.
• Earthquake magnitude scales.
• The principles of hypocentral location.
• Focal mechanisms.
• Recording station operations and seismic networks

14
Sri Lanka Earthquake Tsunami Warning Training
Program
Types of Magnitude Scales
Period Range
ML Local magnitude (California)
regional S and 0.1-1 sec
surface
waves Mj JMA (Japan Meteorol. Agency)
regional S and 5-10 sec
surface
waves mb Body wave magnitude
teleseismic P waves 1-5 sec Ms Surface
wave magnitude teleseismic surface
20 sec
waves Mw Moment magnitude
teleseismic surface gt 200
sec
waves Mwp P-wave moment
magnitude teleseismic P waves 10-60 sec

Mm
Mantle magnitude
teleseismic surface gt 200 sec

waves
15
Sri Lanka Earthquake Tsunami Warning Training
Program
Relationship between different types of magnitudes
Handout pages 65-69, 118-121, 125-126
16
Sri Lanka Earthquake Tsunami Warning Training
Program

• Key topics covered in the seismology component of
  the course
• Global distribution and frequency of earthquakes.
• Elastic rebound theory.
• The particle motion and path through the Earth of
  major seismic phases (P, S, Surface waves).
• Identification of P, S and surface wave arrivals
  on a seismogram.
• Earthquake magnitude scales.
• The principles of hypocentral location.
• Focal mechanisms.
• Recording station operations and seismic networks

17
Sri Lanka Earthquake Tsunami Warning Training
Program

• hypocentral locations

Handout pages 64, 115-117 Dr Kayals notes on
the CD
. Whole Earth Geophysics by Robert J. Lillie
18
Sri Lanka Earthquake Tsunami Warning Training
Program

• Key topics covered in the seismology component of
  the course
• Global distribution and frequency of earthquakes.
• Elastic rebound theory.
• The particle motion and path through the Earth of
  major seismic phases (P, S, Surface waves).
• Identification of P, S and surface wave arrivals
  on a seismogram.
• Earthquake magnitude scales.
• The principles of hypocentral location.
• Focal mechanisms.
• Recording station operations and seismic networks

19
Sri Lanka Earthquake Tsunami Warning Training
Program
. Whole Earth Geophysics by Robert J. Lillie
Handout pages 73-75, 98-100, 122-124
20
Sri Lanka Earthquake Tsunami Warning Training
Program

• Key topics covered in the seismology component of
  the course
• Global distribution and frequency of earthquakes.
• Elastic rebound theory.
• The particle motion and path through the Earth of
  major seismic phases (P, S, Surface waves).
• Identification of P, S and surface wave arrivals
  on a seismogram.
• Earthquake magnitude scales.
• The principles of hypocentral location.
• Focal mechanisms.
• Recording station operations and seismic networks

21
Sri Lanka Earthquake Tsunami Warning Training
Program
Vault of an observatory
Handout pages 127-130
22
Sri Lanka Earthquake Tsunami Warning Training
Program
Handout pages 131-132