China seismic intensity scale
The China seismic intensity scale (CSIS) is a national standard in the
EMS-92 on which CSIS drew reference, seismic impacts are classified into 12 degrees of intensity, or liedu (Chinese: 烈度; pinyin: lièdù, literally "degrees of violence") in Roman numerals
from I for insensible to XII for landscape reshaping.
The scale was initially formalized by the
Guobiao, series GB/T 17742-1999 by then National Quality and Technology Supervision Administration (now General Administration of Quality Supervision, Inspection, and Quarantine of P.R.C., AQSIQ) in 1999.[2]
The standard was set for revision not long before the 2008 Sichuan earthquake.[3]
Liedu scale
Unlike the
magnitude scales
that objectively estimate the released seismic energy, liedu denotes how strongly an earthquake affects a specific place. It is determined by a combination of subjective evaluations (such as human senses and building damage) and objective kinetic measures. Building damage are further refined with a combination of descriptive qualifiers and a numeric evaluation process.
The following is an unofficial translation of the Appendix I of GB/T 17742-1999.
Liedu (Intensity) | Senses by people on the ground | Degree of building damage | Other damage | Horizontal motion on the ground | ||
---|---|---|---|---|---|---|
Damage | Mean damage index | Peak acceleration m/s2 | Peak speed m/s | |||
I | Insensible | |||||
II | Sensible by very few still indoor people | |||||
III | Sensible by a few still indoor people | Slight rattle of doors and windows | Slight swing of suspended objects | |||
IV | Sensible by most people indoors, a few people outdoors; a few wake up from sleep | Rattle of doors and windows | Obvious swing of suspended objects; vessels rattle | |||
V | Commonly sensible by people indoors, sensible by most people outdoors; most wake up from sleep | Noise from vibration of doors, windows, and building frames; falling of dusts, small cracks in plasters, falling of some roof tiles, bricks falling from a few roof-top chimneys | Rocking or flipping of unstable objects | 0.31 (0.22 - 0.44) |
0.03 (0.02 - 0.04) | |
VI | Most unable to stand stably, a few scared to running outdoors | Damage - Cracks in the walls, falling of roof tiles, some roof-top chimneys crack or fall apart | 0 - 0.10 | Cracks in river banks and soft soil; occasional burst of sand and water from saturated sand layers; cracks on some standalone chimneys | 0.63 (0.45 - 0.89) |
0.06 (0.05 - 0.09) |
VII | Majority scared to running outdoors, sensible by bicycle riders and people in moving motor vehicles | Slight destruction - localized destruction, crack, may continue to be used with small repairs or without repair | 0.11 - 0.30 | Collapse of river banks; frequent burst of sand and water from saturated sand layers; many cracks in soft soils; moderate destruction of most standalone chimneys | 1.25 (0.90 - 1.77) |
0.13 (0.10 - 0.18) |
VIII | Most swing about, difficult to walk | Moderate destruction - structural destruction occurs, continued usage requires repair | 0.31 - 0.50 | Cracks appear in hard dry soils; severe destruction of most standalone chimneys; tree tops break; death of people and cattle caused by building destruction | 2.50 (1.78 - 3.53) |
0.25 (0.19 - 0.35) |
IX | Moving people fall | Severe destruction - severe structural destruction, localized collapse, difficult to repair | 0.51 - 0.70 | Many cracks in hard dry soils; possible cracks and dislocations in bedrock; frequent landslides and collapses; collapse of many standalone chimneys | 5.00 (3.54 - 7.07) |
0.50 (0.36 - 0.71) |
X | Bicycle riders may fall; people in unstable state may fall away; sense of being thrown up | Most collapse | 0.71 - 0.90 | Cracks in bedrock and earthquake fractures; destruction of bridge arches founded in bedrock; foundation damage or collapse of most standalone chimneys | 10.00 (7.08 - 14.14) |
1.00 (0.72 - 1.41) |
XI | Widespread collapse | 0.91 - 1.00 | Earthquake fractures extend a long way; many bedrock cracks and landslides | |||
XII | Drastic change in landscape, mountains, and rivers |
Notes about qualifiers: "very few" - <10%; "few" - 10% - 50%; "most" - 50% - 70%; "majority" - 70% - 90%; "commonly" - >90%.
Applications
Historic local seismic liedu is an important reference in quake proofing existing and future buildings. The national standard Code for Seismic Design of Buildings (GB 500011-2001) published in 2001 and partially revised shortly after the 2008 Sichuan earthquake includes a list of liedu that each building in designated cities is expected to resist.[4]
See also
- Seismic intensity scales
- Seismic magnitude scales
- Seismic engineering
Notes and references
- ^ Effectively this only applies to mainland China. Hong Kong and Taiwan each use a different intensity scale. See Seismic intensity scales for more details.
- ^ a b CHEN Dasheng, SHI Zhenliang, XU Zonghe, GAO Guangyi, NiAN Jiaquan, XIAO Chengye, FENG Yijun (陈达生、时振梁、徐宗和、高光伊、鄢家全、肖承邺、冯义钧) (1999-04-26). "China Seismic Intensity Scale (中国地震烈度表)" (in Chinese). General Administration of Quality Supervision, Inspection, and Quarantine of P.R.C. Archived from the original on 2008-10-29. Retrieved 2008-09-12.
{{cite web}}
: CS1 maint: multiple names: authors list (link) - ^ "Revision of "China Seismic Intensity Scale" started (《中国地震烈度表》修订工作启动)" (in Chinese). China Earthquake Administration (中国地震局). 1999-04-26. Retrieved 2008-09-12.
- ^ XU Zhengzhong, WANG Yayong, et al. (徐正忠、王亚勇等) (2001). "Code for seismic design of buildings (GB 500011-2001) (partially revised in 2008), Appendix A ( 《建筑抗震设计规范》(GB 500011-2001) (2008 年局部修订) 附录 A 我国主要城镇抗震设防烈度、设计基本地震加速度和设计地震分组)". Ministry of Housing and Urban-Rural Development of PRC (MOHURD, 中华人民共和国住房和城乡建设部). Retrieved 2008-09-15.
{{cite web}}
: CS1 maint: multiple names: authors list (link)
External links
- Spencer, B.F.; Hu, Y. X. (2001). Earthquake Engineering Frontiers in the New Millennium: Proceedings of the China-US Millennium Symposium on Earthquake Engineering, Beijing, 8–11 November 2000. Taylor & Francis. ISBN 978-90-265-1852-2.