Arrowsmith next to dark fiber under SMU (IMAGE) Southern Methodist University Caption Arrowsmith next to unused fiber optic cables (dark fiber), which have been transformed into seismic sensors that detect vibrations. Credit SMU Usage Restrictions None License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.