Seafloor geophysical instrumentation is challenging to deploy and maintain but critical for studying submarine earthquakes and Earth’s interior. Emerging fiber-optic sensing technologies that can leverage submarine telecommunication cables present an opportunity to fill the data gap. We successfully sensed seismic and water waves over a 10,000-kilometer-long submarine cable connecting Los Angeles, California, and Valparaiso, Chile, by monitoring the polarization of regular optical telecommunication channels. We detected multiple moderate-to-large earthquakes along the cable in the 10-millihertz to 5-hertz band. We also recorded pressure signals from ocean swells in the primary microseism band, implying the potential for tsunami sensing. Our method, because it does not require specialized equipment, laser sources, or dedicated fibers, is highly scalable for converting global submarine cables into continuous real-time earthquake and tsunami observatories.

海底地球物理仪器的部署和维护具有挑战性，但对于研究海底地震和地球内部至关重要。可以利用海底电信电缆的新兴光纤传感技术为填补数据空白提供了机会。通过监视常规光通信信道的极化，我们成功地通过了一条10,000公里长的海底电缆，将地震波和水波感应到连接加利福尼亚州洛杉矶和智利瓦尔帕莱索的海底电缆。我们在10兆赫兹到5赫兹波段的电缆上检测到多次中到大地震。我们还记录了主要微地震带中来自海浪的压力信号，这暗示了海啸传感的潜力。我们的方法，因为它不需要专门的设备，激光源或专用光纤，