Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

Session IV.3

Review of the Seismology component of the training course

April 6, 2006

Sri Lanka

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri 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

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

Handout pages 63, 75-80

Frequency distribution of earthquakes

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

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

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri 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

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

Elastic Rebound Theory

Handout pages: 62, 95

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri 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

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

Handout pages:48-60, 72

Forward Branch

Backward Branch

Forward Branch

Shadow Zone

P waves

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

Ray paths

. “Whole Earth Geophysics” by Robert J. Lillie

Handout pages:82-94

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri 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

Love Waves

vertical

radial

transverse

Rayleigh Waves

P S

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

Handout page 70

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri 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

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

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 wavesMw Moment magnitude teleseismic surface > 200 sec wavesMwp P-wave moment magnitude teleseismic P waves 10-60 sec

Mm Mantle magnitude teleseismic surface > 200 sec

waves

Types of Magnitude ScalesPeriod Range

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

Relationship between different types of magnitudes

Handout pages:65-69, 118-121, 125-126

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri 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

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

hypocentral locations

. “Whole Earth Geophysics” by Robert J. Lillie

Handout pages:64, 115-117 & Dr Kayal’s notes on the CD

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri 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

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

. “Whole Earth Geophysics” by Robert J. Lillie

Handout pages 73-75, 98-100, 122-124

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri 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

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

Vault of an observatory

Handout pages:127-130

Sri Lanka Earthquake & Tsunami Warning Training ProgramSri Lanka Earthquake & Tsunami Warning Training Program

Handout pages 131-132