The recent discovery of gravitational waves (GWs) and their potential for cosmic observations prompted the design of the future third‐generation GW interferometers, able to extend the observation distance for sources up to the frontier of the Universe. In particular, the European detector Einstein Telescope (ET) has been proposed to reach peak strain sensitivities of about 3×10−25 Hz−1/2 in the 100 Hz frequency region and to extend the detection band down to 1 Hz. In the bandwidth [1,10] Hz, the seismic ambient noise is expected to represent the major perturbation to interferometric measurements, and the site that will host the future detectors must fulfill stringent requirements on seismic disturbances. In this article, we conduct a seismological study at the Italian ET candidate site, the dismissed mine of Sos Enattos in Sardinia. In the range between few mHz to hundreds of mHz, out of the detection bandwidth for ET, the seismic noise is compatible with the new low‐noise model (Peterson, 1993); in the [0.1,1] Hz bandwidth, we found that seismic noise is correlated with sea wave height in the northwestern Mediterranean Sea. In the [1,10] Hz frequency band, noise is mainly due to anthropic activities; within the mine tunnels (⁠≃100 m underground), its spectrum is compliant with the requirements of the ET design. Noise amplitude decay with depth is consistent with a dominance of Rayleigh waves, as suggested by synthetic seismograms calculated for a realistic velocity structure obtained from the inversion of phase‐ and group‐velocity dispersion data from array recording of a mine blasting. Further investigations are planned for a quantitative assessment of the principal noise sources and their spatiotemporal variations.

中文翻译：

---

Sos Enattos地区的地震研究-爱因斯坦望远镜的撒丁岛候选地点

引力波（GW）的最新发现及其在宇宙观测中的潜力促使了未来第三代GW干涉仪的设计，从而能够将源的观测距离扩展到宇宙的最前沿。尤其是，已经提出了欧洲探测器爱因斯坦望远镜（ET）可以在100 Hz频率范围内达到约3×10-25 Hz-1 / 2的峰值应变敏感度，并将检测频带扩展到1 Hz。在[1,10] Hz带宽中，预期地震环境噪声将代表对干涉测量的主要干扰，而容纳未来探测器的地点必须满足对地震干扰的严格要求。在本文中，我们在意大利ET候选地点（位于撒丁岛的Sos Enattos废弃矿山）进行了地震学研究。在几兆赫兹到几百兆赫兹之间的范围内，在ET的检测带宽之外，地震噪声与新的低噪声模型兼容（Peterson，1993）。在[0.1,1] Hz带宽中，我们发现地震噪声与西北地中海的海浪高度相关。在[1,10] Hz频带中，噪声主要是由于人类活动造成的；在矿井隧道内（地下约100 m），其频谱符合ET设计的要求。噪声振幅随深度的衰减与瑞利波的优势一致，这是通过合成的地震图计算得出的，该合成的地震图是通过对爆破阵列记录的相速度和群速度色散数据进行反演而获得的真实速度结构而计算出的。