Rotaphone, a Self-Calibrated Six-Degree-of-Freedom Seismic Sensor and Its Strong-Motion Records

In this paper we present a new six-degree-of-freedom (6DOF) seismic sensor called Rotaphone and its strong-motion records both from an anthropogenic source (blast) and from a tectonic event. By strong rotational motion we mean rotation rate of the order 10−4 rad/s and higher (according to a common convention accepted in the seismological community; see, e.g., Graizer, 2009). The sensor is portable, and easy to install and operate. It has a wide dynamic range of 120 dB; it is able to detect weak ground motions (from the order of 10−7 in SI units) as well as stronger motions (up to the order of 10−1 in SI units). The sensor seems to meet requirements of operative deployment for the needs of strong rotational ground-motion studies.