China Seismic Intensity Scale
Encyclopedia
The China Seismic Intensity Scale (CSIS) is a national standard in the People's Republic of China
used to measure seismic intensity. Similar to EMS-92
on which CSIS drew reference, seismic impacts are classified into 12 degrees of intensity, or liedu in Roman numerals
from I for insensible to XII for landscape reshaping.
The scale was initially formalized by the China Earthquake Administration
(CEA) in 1980, therefore often referred to by its original title as "China Seismic Intensity Scale (1980)". It was later revised, and adopted as a national standard, or 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.
The standard was set for revision not long before the 2008 Sichuan earthquake
.
The following is an unofficial translation of the Appendix I of GB/T 17742-1999.
Notes about Qualifiers: "very few" - <10%; "few" - 10% - 50%; "most" - 50% - 70%; "majority" - 70% - 90%; "commonly" - >90%.
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.
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
used to measure seismic intensity. Similar to EMS-92
European Macroseismic Scale
The European Macroseismic Scale is the basis for evaluation of seismic intensity in European countries and is also used in a number of countries outside Europe...
on which CSIS drew reference, seismic impacts are classified into 12 degrees of intensity, or liedu in Roman numerals
Roman numerals
The numeral system of ancient Rome, or Roman numerals, uses combinations of letters from the Latin alphabet to signify values. The numbers 1 to 10 can be expressed in Roman numerals as:...
from I for insensible to XII for landscape reshaping.
The scale was initially formalized by the China Earthquake Administration
China Earthquake Administration
The China Earthquake Administration , is mandated by the Law of the People's Republic of China on Protecting Against and Mitigating Earthquake Disasters of PRC to enforce the earthquake administration in the nation under the administration of State Council of the People's Republic of China.Some...
(CEA) in 1980, therefore often referred to by its original title as "China Seismic Intensity Scale (1980)". It was later revised, and adopted as a national standard, or 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.
The standard was set for revision not long before the 2008 Sichuan earthquake
2008 Sichuan earthquake
The 2008 Sichuan earthquake or the Great Sichuan Earthquake was a deadly earthquake that measured at 8.0 Msand 7.9 Mw occurred at 14:28:01 CST...
.
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 damages) and objective kinetic measures. Building damages 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 damages | Horizontal motion on the ground | ||
|---|---|---|---|---|---|---|
| Damages | Mean damage index | Peak acceleration Peak ground acceleration Peak ground acceleration is a measure of earthquake acceleration on the ground and an important input parameter for earthquake engineering, also known as the design basis earthquake ground motion... 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 | Damages - 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 | Wide spread 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 proofingEarthquake engineering
Earthquake engineering is the scientific field concerned with protecting society, the natural and the man-made environment from earthquakes by limiting the seismic risk to socio-economically acceptable levels...
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
2008 Sichuan earthquake
The 2008 Sichuan earthquake or the Great Sichuan Earthquake was a deadly earthquake that measured at 8.0 Msand 7.9 Mw occurred at 14:28:01 CST...
includes a list of liedu that each building in designated cities is expected to resist.