GB/T 19531.1-2026 Technical requirements for the observation environment of seismic stations—Part 1: Seismometry English, Anglais, Englisch, Inglés, えいご
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ICS 13.220.10
CCS H 57
National Standard of the People's Republic of China
GB/T 19531.1-2026
Replaces GB/T 19531.1-2004
Technical requirements for the observation environment of seismic stations - Part 1: Seismometry
地震台站观测环境技术要求 第1部分：测震
Issue date: 2026-01-28 Implementation date: 2027-02-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
Introduction
1 Scope
2 Normative References
3 Terms and Definitions
4 Symbols
5 Ambient Ground Noise Level
6 Minimum Distance Between Seismometer Location and Main Interference Sources
7 Attenuation Relationship of Ground Noise Level with Depth
Annex A (Normative) Calculation of Ambient Ground Noise Level
Annex B (Normative) Regional Division of Background Ground Noise in China's Land Area
Bibliography
Technical Requirements for the Observational Environment of Seismic Stations — Part 1: Seismometry
1 Scope
This document specifies the technical specifications for the seismometric observational environment of seismic stations, the minimum distance requirements between the seismometer location and main interference sources, and describes the corresponding test and calculation methods.
This document applies to the site selection and environmental protection for the observation of seismic stations (ground motion velocity observation).
2 Normative References
The following documents contain provisions which, through normative reference in this text, constitute essential provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 18207 (all parts) Terms Relating to Protecting Against and Mitigating Earthquake Disasters
GB/T 29716.1-2013 Mechanical Vibration and Shock — Signal Processing — Part 1: General Introduction
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 18207 (all parts) and the following apply.
3.1
ground noise
Ground vibrations caused by non-seismic sources.
3.2
ground noise level
The root mean square value of the power spectral density of the velocity record of ground noise (3.1) within the frequency band of 1 Hz to 20 Hz.
3.3
background ground noise
The average ground noise (3.1) over a regional scale.
3.4
ambient ground noise
The sum of the background ground noise (3.3) at a specific location and other interfering ground noises.
4 Symbols
The following symbols apply to this document.
Eₙₗ — Ambient ground noise level, in meters per second (m/s).
Eₙₗ, dB — Ambient ground noise level expressed in decibels (dB).
Pᵥ — Power spectral density of ground motion velocity, in square meters per square second per Hertz [(m/s)²/Hz].
5 Ambient Ground Noise Level
5.1 Calculation of Ambient Ground Noise Level
A velocity-type seismometer shall be used to observe and record ground noise. The ambient ground noise level Eₙₗ shall be calculated according to the provisions of Annex A.
5.2 Classification of Ambient Ground Noise Level Grades
The ambient ground noise level grades are divided into the following 6 levels:
a) Grade I ambient ground noise level: Eₙₗ < 3.16 × 10⁻⁸ m/s;
b) Grade II ambient ground noise level: 3.16 × 10⁻⁸ m/s ≤ Eₙₗ < 1.00 × 10⁻⁷ m/s;
c) Grade III ambient ground noise level: 1.00 × 10⁻⁷ m/s ≤ Eₙₗ < 3.16 × 10⁻⁷ m/s;
d) Grade IV ambient ground noise level: 3.16 × 10⁻⁷ m/s ≤ Eₙₗ < 1.00 × 10⁻⁶ m/s;
e) Grade V ambient ground noise level: 1.00 × 10⁻⁶ m/s ≤ Eₙₗ < 3.16 × 10⁻⁶ m/s;
f) Grade VI ambient ground noise level: Eₙₗ ≥ 3.16 × 10⁻⁶ m/s.
The above ambient ground noise level grades expressed in decibels are:
a) Grade I ambient ground noise level: Eₙₗ,dB < -150 dB;
b) Grade II ambient ground noise level: -150 dB ≤ Eₙₗ,dB < -140 dB;
c) Grade III ambient ground noise level: -140 dB ≤ Eₙₗ,dB < -130 dB;
d) Grade IV ambient ground noise level: -130 dB ≤ Eₙₗ,dB < -120 dB;
e) Grade V ambient ground noise level: -120 dB ≤ Eₙₗ,dB < -110 dB;
f) Grade VI ambient ground noise level: Eₙₗ,dB ≥ -110 dB.
5.3 Determination of the Background Noise Region for a Specific Station
Based on the spatial distribution of background ground noise levels in China's land area, the land area is divided into five background ground noise regions: A, B, C, D, and E. The background ground noise for a specific station shall be determined according to the provisions of Annex B.
5.4 Requirements for Observational Ambient Ground Noise Level for Various Station Types
5.4.1 Short-Period Seismometer Stations
For stations where short-period seismometers are installed, the ambient ground noise level in various regions shall comply with the following requirements:
a)Region A: not exceeding Grade II ambient ground noise level;
b) Region B: not exceeding Grade III ambient ground noise level;
c) Region C: not exceeding Grade III ambient ground noise level;
d) Region D: not exceeding Grade IV ambient ground noise level;
e) Region E: not exceeding Grade V ambient ground noise level.
5.4.2 Broadband Seismometer Stations
For stations where broadband seismometers are installed, the ambient ground noise level in various regions shall comply with the following requirements:
a) Region A: not exceeding Grade II ambient ground noise level;
b) Region B: not exceeding Grade II ambient ground noise level;
c) Region C: not exceeding Grade III ambient ground noise level;
d) Region D: not exceeding Grade III ambient ground noise level;
e) Region E: not exceeding Grade IV ambient ground noise level.
5.4.3 Borehole Seismometer Stations
The ambient ground noise level at the location where the seismometer is installed shall meet the observational ambient ground noise level requirements for that type of seismometer in the corresponding background ground noise region.
5.4.4 Stations with Multiple Seismometers Co-located
For stations equipped with two or more types of seismometers simultaneously, the ambient ground noise level shall meet the most stringent ambient ground noise level requirement among all seismometer types present at the station.
6 Minimum Distance Between Seismometer Location and Main Interference Sources
6.1 The minimum distance between the seismometer location and main interference sources shall comply with the requirements specified in Table 1.
6.2 The minimum distance between a station with Grade I, III, IV, or V ambient ground noise level and a main interference source equals the product of the minimum distance for a Grade II ambient ground noise level station from the interference source and the minimum distance scaling factor for that grade of station.
6.3 For interference sources not listed in Table 1 or for sites with special geological characteristics, it is recommended to use equipment of the same type as the planned seismometer to conduct actual ambient ground noise level tests at various distances to assess the minimum distance between the seismometer location and the interference source.
7 Attenuation Relationship of Ground Noise Level with Depth
If the surface seismometer location does not meet the requirements of Table 1 and the interference source cannot be avoided, a borehole installation method may be used. The attenuation relationship of ground noise level with depth is shown in Table 2. This table represents the relationship between the average ground noise level and depth change under a typical sedimentary plain geological setting. Note that Table 2 is not applicable to Region E defined in Annex B.
