2 Terms and Symbols
2.1 Terms
2.1.1 Seismicity
The distribution law and features of earthquakes occurring within given period of time and space in intensity，frequency，time and space.
2.1.2 Seismotectonics
Tectonic structure related to the breeding and occurrence of earthquakes.
2.1.3 Seismotectonic model
Calculation model established on the basis of regional seismotectonic background and features for deterministic evaluation of seismic hazard.It consists of maximum potential earthquake of the seismogenic structure and diffuse earthquake in seismotectonic province.
2.1.4 Seismogenic structure
A geologic structure where a destructive earthquake has occurred or may occur.
2.1.5 Capable fault
A fault that may possibly cause obvious dislocation on or near the ground surface.
2.1.6 Maximum potential earthquake
The maximum earthquake that may occur in the seismogenic structure.
2.1.7 Seismotectonic province
A geographic area with identical geologic structure and seismic activity.
2.1.8 Diffuse earthquake
The maximum potential earthquake having been determined as irrelevant to the confirmed seismogenic structure in a seismotectonic province.
2.1.9 Potential seismic source zone
A zone where destructive earthquake may occur in the future.
2.1.10 Upper limit magnitude
The limit of possible seismic magnitude in a seismic belt or potential seismic source zone in the probabilistic seismic hazard analysis.
2.1.11 Probability of exceedance
The probability of a random variable exceeding a given value.
2.1.12 Ground motion
The ground surface motion caused by an earthquake.
2.1.13 Attenuation relationship of ground motion
The empirical formula to express the statistic relationship of ground motion parameters with seismic magnitude，focus characteristics，propagation characteristics and ground conditions.
2.1.14 Ground motion parameter
The physical parameters expressing the ground motion caused by an earthquake，including peak value，response spectrum and duration.
2.1.15 Site specific ground motion
The ground motion parameters of a specific site obtained on the basis of the seismotectonic background and ground conditions of the site.
2.1.16 Design basis ground motion
The ground motion parameters that must be satisfied in the design of a nuclear power plant.
2.1.17 Seismic level 2 ground motion
The ground motion corresponding to the ultimate safety requirements of a nuclear power plant.
2.1.18 Upper value of seismic level 2 ground motion
A conservatively estimated value given for seismic level 2 ground motion peak acceleration of the site in the preliminary feasibility study phase.
2.1.19 Seismic level 1 ground motion
The ground motion corresponding to the safe operation requirements of a nuclear power plant.
2.1.20 Design time history of ground motion
The ground motion time process used in the anti-seismic design for nuclear power plants.