Recording active-seismic ground rotations using induction-coil magnetometers

Barak, Ohad; Key, Kerry; Constable, Steven; Ronen, Shuki

doi:10.1190/geo2017-0281.1

Cited by 5 publications

(1 citation statement)

References 34 publications

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“…Barak et al [131] recognized that conventional induction-coil magnetometers can potentially be used to measure ground rotational motions since a rotation of the sensor results in a change in the projection of the Earth's magnetic field on the three orthogonal magnetometer components.…”

Section: Direct Observationsmentioning

confidence: 99%

Seismological Processing of Six Degree-of-Freedom Ground-Motion Data

Sollberger

Igel

Schmelzbach

et al. 2020

Sensors

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Recent progress in rotational sensor technology has made it possible to directly measure rotational ground-motion induced by seismic waves. When combined with conventional inertial seismometer recordings, the new sensors allow one to locally observe six degrees of freedom (6DOF) of ground-motion, composed of three orthogonal components of translational motion and three orthogonal components of rotational motion. The applications of such 6DOF measurements are manifold—ranging from wavefield characterization, separation, and reconstruction to the reduction of non-uniqueness in seismic inverse problems—and have the potential to revolutionize the way seismic data are acquired and processed. However, the seismological community has yet to embrace rotational ground-motion as a new observable. The aim of this paper is to give a high-level introduction into the field of 6DOF seismology using illustrative examples and to summarize recent progress made in this relatively young field. It is intended for readers with a general background in seismology. In order to illustrate the seismological value of rotational ground-motion data, we provide the first-ever 6DOF processing example of a teleseismic earthquake recorded on a multicomponent ring laser observatory and demonstrate how wave parameters (phase velocity, propagation direction, and ellipticity angle) and wave types of multiple phases can be automatically estimated using single-station 6DOF processing tools. Python codes to reproduce this processing example are provided in an accompanying Jupyter notebook.

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Section: Direct Observationsmentioning

confidence: 99%

Seismological Processing of Six Degree-of-Freedom Ground-Motion Data

Sollberger

Igel

Schmelzbach

et al. 2020

Sensors

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Rotational Seismology with a Quartz Rotation Sensor

Venkateswara

Paros

Bodin

et al. 2021

Seismological Research Letters

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We describe the construction and performance of a new high-precision ground- or platform-rotation sensor called the Quartz Rotation Sensor (QRS). The QRS is a mechanical angular accelerometer that senses rotational torque with an inherently digital, load-sensitive resonant quartz crystal. The noise floor is measured to be ∼45 pico-radians/root (Hz) near 1 Hz, and the resonant period of the sensor is about 10 s, making it a broadband sensor. Among similarly sized broadband rotation sensors, this represents more than two orders of magnitude improvement in noise floor near 0.1 Hz. We present measurements of rotational components of teleseismic waves recorded with the sensor at a vault. The QRS is useful for rotational seismology and for improving low-frequency seismic isolation in demanding applications such as the Laser Interferometer Gravitational-Wave Observatories.

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Development of a High-Precision Deep-Sea Magnetic Survey System for Human-Occupied Vehicles

Zhang,

Zhou,

Deng

et al. 2024

Electronics

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The high-precision magnetic survey system is crucial for ocean exploration. However, most existing systems face challenges such as high noise levels, low sensitivity, and inadequate magnetic compensation effects. To address these issues, we developed a high-precision magnetic survey system based on the manned submersible “Deep Sea Warrior” for deep-ocean magnetic exploration. This system incorporates a compact optically pumped cesium (Cs) magnetometer sensor to measure the total strength of the external magnetic field. Additionally, a magnetic compensation sensor is included at the front end to measure real-time attitude changes of the platform. The measured data are then transmitted to a magnetic signal processor, where an algorithm compensates for the platform’s magnetic interference. We also designed a deep pressure chamber to allow for a maximum working depth of 4500 m. Experiments conducted in both indoor and field environments verified the performance of the proposed magnetic survey system. The results showed that the system’s sensitivity is ≤0.5 nT, the noise level of the magnetometer sensor is ≤1 pT/√Hz at 1 Hz, and the sampling rate is 10 Hz. The proposed system has potential applications in ocean and geophysical exploration.

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Recording active-seismic ground rotations using induction-coil magnetometers

Cited by 5 publications

References 34 publications

Seismological Processing of Six Degree-of-Freedom Ground-Motion Data

Seismological Processing of Six Degree-of-Freedom Ground-Motion Data

Rotational Seismology with a Quartz Rotation Sensor

Development of a High-Precision Deep-Sea Magnetic Survey System for Human-Occupied Vehicles

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