China seismic intensity scale

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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 scale[2]
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

Notes and references

  1. ^ Effectively this only applies to mainland China. Hong Kong and Taiwan each use a different intensity scale. See Seismic intensity scales for more details.
  2. ^ 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)
  3. ^ "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.
  4. ^ 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. .