Global seismic network in operation for 40 years
• Global seismic network in operation for ~40 years provides a huge database of information on earthquakes: • Location, Depth • Magnitude, Frequency • Total Energy released • Type of Faulting and orientation of fault planes • State of stress in brittle material
Subduction (Indonesia)
Terminology
• A typical seismogram and determination of range
Earthquake Locations • Accuracy ~ 10 km, slightly larger error in depth. • Geographic distribution: Pattern of plate boundaries
Energy and Polarity of “First Motions”
Earthquake on a vertical plane
Determination of nodal planes
Spreading of the seismic wave
Data on the surface, interpreted as a section
Azimuth (f) and take-off angle
In General have we seismic data from faults with any orientations – plot a stereogram
Fault types and “Beach Ball” plots
Example Focal mechanism diagrams on the Azores. Gibraltar fracture zone
Seismic Focal Mechanisms: Summary &Applications • Detection at a distance via the world network Energy and Polarity of “First Motions” • Plot polarity against azimuth and “take-off angle” • Determine orientation of Fault-plane • [explosions v. earthquakes]
Brief Facts About: By Dr. Qamar-uz-Zaman Chaudhary Director General Pakistan Meteorological Department pmd@pakmet. com. pk
Pakistan Meteorological Department
Seismogram
PAST SEISMIC HISTORY OF PAKISTAN
Earthquake in Quetta: 1935 7. 7 35, 000 Railway Station
Earthquake in Quetta: 1935 7. 7 35, 000 Lytton Road
Earthquake in Pakistan: 1892 6. 8 Chaman: Balochistan
Earthquake in Kangra: 1905 7. 8 Himachal Pradesh 19, 727 Town Hall Lahore Before After
M 7. 5 KASHMIR EARTHQUAKE ON OCTOBER 8, 2005
PAKISTAN METEOROLOGICAL DEPARTMENT M 7. 5 EARTHQUAKE OF 8 TH OCTOBER 2005 IN NORTHERN PAKISTAN EPICENTRE: 34. 4°N, 73. 5°E DEPTH: 10 KM
Shake. Map OF OCTOBER 8, 2005 EARTHQUAKE
KNOW THE RISK FOR FUTURE MITIGATION
Up-gradation of National Seismic Network for Pakistan (Approved June, 2005) National Seismic Control Room Peshawar National Geophysical Centre Quetta Chitral Mansehra Zhob Khuzdar Turbat National Tsunami Early Warning Centre (TWC), Karachi Muzaffarabad
Establishment of Tsunami Warning Center in Pakistan Backup Tsunami Warning Centers Information to Regional / Global Mitigation Centers Linkage with other Regional /Global TWS National Tsunami Early Warning Centre (TWC), Karachi
Thank You All
- Slides: 40