几种旋转地震仪在深部地下巷道的观测对比

光纤旋转地震仪具有宽频带、高灵敏度、便携等优点，在地震旋转运动的观测中有着广阔的应用前景.光学旋转地震仪的性能会受观测环境噪声的影响，因此，在低噪环境下测试仪器的自噪声、验证其对远震信号的分辨能力是非常有意义的.利用淮南停产的潘一东煤矿-848 m的地下巷道空间，我们开展了深部地下地震联合观测试验，对比了R-2型电化学式旋转地震仪与FOS1、FOS2、FOS3三种光纤旋转地震仪的自噪声水平，及其记录的远震Love波信号垂向旋转分量与切向加速度的相干性.观测与分析结果表明：光纤旋转地震仪的灵敏度高于R-2电化学式；较小的体积使得FOS3型六分量地震计的自噪声较高，而相对大体积的FOS1型单分量与FOS2型双分量光纤旋转地震计具有更低的自噪声和Allan方差，能有效捕获1000 km左右的远震旋转信号，且二者观测地震事件的波形具有较高的一致性.表明深地环境可用于光纤旋转地震仪的自噪声测试和比对，且有助于国内旋转地震仪性能的提高.

Deep underground observation comparison of rotational seismometers

In the observation of seismic rotational motion, fiber-optic seismometers with wide frequency band, high sensitivity and portability have broad application prospects. The performance of fiber-optic rotational sensors is affected by the ambient noise of the observation environment. Therefore, it is of great significance to test the limit of instrument self-noise and verify its teleseismic signal resolution ability in low-noise environment. In the underground tunnel of the discontinued Huainan Panyi-East Coal Mine, which is located at a depth of -848 meters, we carried out a joint deep underground seismic observation. The self-noise and Love wave recording capabilities of four types of rotational seismometers, including molecular-electronic rotational seismometer (R-2) based on electrochemical technology and three types of fiber-optic rotational seismometers (FOS1/FOS2/FOS3), were compared to figure out instrument sensitivity and characteristics. Results indicate that the sensitivity of the fiber-optic rotational seismometer is higher than that of R-2 electrochemical seismometer; the size of fiber-optic seismometer limits the high self-noise of FOS3 six-component seismometer (three translational components+three rotational components); FOS1 and FOS2 fiber-optic seismometers have lower self-noise and Allan deviation, which can effectively record the teleseismic rotational signals with an epicentral distance of about 1000 km, and the waveforms recorded by the two seismometers keep higher coherence. It can be deduced that the deep underground environment can be used to test and compare the self-noise of fiber-optic rotational seismometers, which will help to understand and improve the performance of rotational seismometers in China.