地震台站噪声水平定量评估及其在气枪源探测中的应用

Quantitative Assessment of Background Noise Levels of Seismic Stations and Their Application in Air-Gun Source Detection

摘要:

对福建气枪源探测实验中所接入315个实时传输台站分1~10 Hz、0.1~1 Hz、10~60 s 3个频段进行台网噪声水平评估研究。统计240个小时的背景噪声记录，得到各台站的噪声水平MODE线，再利用本文提出的全球新高低噪声模型线与MODE线所占面积比来量化台网噪声水平，根据不同色标将台网噪声水平划分为十个等级进行评估，评选出优质台站。进一步研究背景噪声对气枪激发效果的影响，验证了台站接收能力与背景噪声密切相关，分析了不同台基（固定、加密、流动、海底）环境噪声水平的影响，得出环境噪声水平由低到高分别为固定台、加密台、流动台、海底台。通过台网噪声评估能有效提高气枪震源信号的检测能力，也为优质台站重点维护提供重要参考。

Abstract:

In this study, 315 real-time transmission stations in Fujian province were accessed in the active air-gun source detection experiment. The noise levels of the network were estimated in three bands:1-10 Hz, 0.1-1 Hz, and 10-60 s. First, the background noise records during 240 h were counted to obtain the MODE line of the noise level at each station. Then, the area ratio of the global high-noise model line and low-noise model line to the MODE line was used to quantify the noise level of the network. Based on the different color standards, we divided the noise levels of the network into 10 levels for estimation, and thereby got the high-quality stations. The influence of background noise on the explosive effect of the air gun was further studied. It is confirmed that the receiving capability of the station is closely related to the background noise. We analyzed the environmental noise levels of different station bases and concluded that the environmental noise levels from low to high are fixed base, encrypted base, mobile base, and undersea base. The detection ability of the air-gun source signals would be efficiently improved by the noise assessment of the network, which would also provide an important reference for the maintenance of high-quality stations.