Hazard and Vulnerability of Moderate Seismicity Regions presented by Professor Tso-Chien PAN Dean, College of Engineering Director, 25 October 2010 DRM GDLN Session on Earthquake Vulnerability Reduction
Outline Why the focus on Asia General Framework for Seismic Risk Assessment Seismic Hazard Source: Regional Seismicity Site Effects: Soft Soil Amplification of Ground Motions Seismic Vulnerability Exposure: Built Environment Vulnerability: Lightly Reinforced Concrete Joints Summary
Why the focus on Asia Historically, Asia has suffered the most due to catastrophic events. Asia has the largest growth of real assets and urban centers on Earth. This has exacerbated the problems of seismic risk management. Climate Change issues will potentially impact Asia more than any other continent.
Historical Earthquake Loss (1960 2009) Number of killed Rest of the World, 190,000 Number of affected Rest of the World, 32,000,000 Asia, 126,000,000 Asia, 920,000 Total = 1,110,000 Estimated Damage (USD Million) Rest of the World, 133,000 Total = 158,000,000 Asia, 315,000 Total = 448,000 Source: EM-DAT: The OFDA/CRED International Disaster Database www.emdat.be Université Catholique de Louvain Brussels Belgium.
Rapid Growth Top 15 Mega-Cities (2009) 1. Tokyo Japan Asia 33,800,000 2. Seoul South Korea Asia 23,900,000 3. Mexico City Mexico North America 22,900,000 4. Delhi India Asia 22,400,000 5. Mumbai India Asia 22,300,000 6. New York USA North America 21,900,000 7. Sao Paulo Brazil South America 21,000,000 8. Manila Philippines Asia 19,200,000 9. Los Angeles USA North America 18,000,000 10. Shanghai China Asia 17,900,000 11. Osaka Japan Asia 16,700,000 12. Kolkata India Asia 16,000,000 13. Karachi Pakistan Asia 15,700,000 14. Guangzhou China Asia 15,300,000 15. Jakarta Indonesia Asia 15,100,000
General Framework for Seismic Risk Assessment EQ Source Modelling Path Directivity Site Soil Rock Building Response Risk Assessment & Loss Estimate: HAZUS, eg Hazards: Peak Ground Acceleration and/or Spectra Vulnerability: Buildings and Infrastructure
Framework for Seismic Risk Assessment 12 9 6 26 Dec 2004 Penang Malay Peninsula Eurasian Plate Source: Magnitude 7.8 and 8.8 earthquakes Loss Assessment: Direct and Indirect Losses Latitude ( o ) 3 Sm Ni 0 Bt Pekanbaru 52 mm/yr Padang (N10 o E) Sb 13 Sep 2007 03:35:26 Sp 12 Sep 2007 23:49:01-3 28 Mar 2005 & NP SP Palembang 1861 Bengkulu 12 Sep 2007 11:10:26 Scenario A En -6 57 mm/yr Jakarta Scenarios B & C Java 60 mm/yr -9 (N17 o E) 0 500 km Indian-Australian Plate -12 90 93 96 99 102 105 108 111 Longitude ( o ) 1797 Medan Sumatra Sumatran Fault 1833 Path Kuala Lumpur Singapore Site Site Effects Exposures: Buildings & Infrastructure
The Earth s Crustal Plate
Southeast Asia Myanmar Laos Thailand Vietnam Cambodia Philippines Malaysia Brunei Singapore Indonesia
Latitude ( o ) Regional Tectonic Setting 12 9 6 3 0-3 -6-9 Sumatra Fault 2004 52 mm/yr (N10 o E) Sumatra Subduction 57 mm/yr Penang Indian-Australian Plate 60 mm/yr (N17 o E) 0 2005 1861 Malay Peninsula Medan Kuala Lumpur 1833 500 km Pekan Baru Sumatra Singapore Palembang -12 93 96 99 102 105 108 111 Longitude ( o ) Eurasian Plate Java Singapore is located in a stable region on the Eurasian Plate Sumatra subduction (± 650 km away): Shallow dipping Very high seismic potential Sumatra fault (± 450 km away): Right-lateral faulting Total length is 1,900 km Highly segmented
Features of Subduction subduction interface Oceanic fracture zone Sumatran fault Obliquity of subduction has led to formation of the Sumatra fault, within the volcanic arc. Splintering of the subducting oceanic plate occurs along faults within the downgoing slab.
Epicentres of Sumatra EQs with M 6.5 (1960-2004)
Padang, Sumatra Earthquake - 2007.03.06 (Mw=6.3) Evacuation at Suntec City Towers and other high-rise buildings in the central business district area
Bengkulu-Mentawai Earthquake - 2007.09.12 (Mw=8.4)
Bengkulu-Mentawai Earthquake - 2007.09.12-13 (Mw=8.4,7.9,7.0) Historical and 2007 rupture areas
Giant Earthquakes Since 2000 Singapore
Kepulauan Mentawai EQ, Indonesia, M=7.5 (2010-10-25 14:42:22 UTC)
Historical Seismicity Sumatra EQs Felt in Singapore (1833-1996)
Sumatran EQs Felt in Singapore per Decade 25 20 As of 22 July 2010 Number of events 15 10 5 0
Singapore s Waterfront Skyline Classic Change in Exposure due to Urbanization What if the 1833 event recurs? Codes for EQ resistant design of buildings for long-distance EQs (circa 1960) (circa 2000)
Site Effects - Singapore Surface Geology
Buildings Responded to Sumatra Events before Bengkulu EQ
Buildings Responded to Bengkulu EQ
Development of Public Housing Home to a large % of population
Some Structural Systems Slab Block Point Block
Seismic Performance of Reinforced Concrete Columns Brittle Ductile
Seismic Performance: Beam Wide Column Joints
Seismic Performance: Lightly Reinforced Beam-Column Joints
Summary Hazard Assessment: Increased Seismic Activities Number of Sumatra events felt in Singapore Coinciding with high construction activities Vulnerability Assessment: Rapid Urbanization Increased number of buildings and taller buildings Site-Dependent Building Response Softer sites are more responsive to distant earthquakes Lightly Reinforced Concrete Beam-Column Joints Responding differently from RC joints designed for buildings in high-seismic regions
Thank you! Q&A
The 30 Sep 2009 Padang Earthquake Date: 2009/ 9/30 Centroid Time: 10:16:17.4 GMT Lat= -0.74 Lon= 99.69 Depth= 75.8 Half duration=14.5 Centroid time minus hypocenter time: 8.4 Moment Tensor: Expo=27 1.790-0.721-1.070 0.654-0.993-1.770 Mw = 7.5 mb = 7.6 Ms = 7.6 Scalar Moment = 2.64e+27 Fault plane: strike=72 dip=51 slip=136 Fault plane: strike=193 dip=58 slip=49
Christchurch, NZ, Earthquake, M=7.1, 4 Sept 2010 Occurred at a location away from the well known Fault Line: Alpine Fault Fault ruptured has remained dormant for 16,000 years. 7.1, 3 rd September 2010
Damage of Masonry Components