Low-frequency terrestrial gravitational-wave detectors

Harms, J.; Slagmolen, B. J. J.; Adhikari, R. X.; Miller, M. Coleman; Evans, M.; Chen, Yanbei; Müller, Holger; Ando, Masaki

doi:10.1103/physrevd.88.122003

Cited by 104 publications

(163 citation statements)

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“…Several concepts have been proposed for gravity strainmeters that target signals between 10 mHz and 10 Hz. These include atom-interferometric, laserinterferometric, torsion-bar, and superconducting gravity strainmeters (Moody et al 2002;Harms et al 2013). While none of the concepts has reached the sensitivity yet required for the detection of earthquake transients, sensitivities of 10 −15 Hz −1/2 in the region 0.1-1 Hz seem within reach.…”

Section: Sensitivity Of Low-frequency Gravity Strainmetersmentioning

confidence: 99%

“…In fact, some of the modern concepts of low-frequency gravity strainmeters evolved from wellknown gravity gradiometer technology. We also want to emphasize that the sensitivity of low-frequency gravity strainmeters required for the detection of earthquake transients lies well below the sensitivity required for GW detection at the same frequencies, which is about 10 −19 Hz −1/2 at 0.1 Hz (Harms et al 2013). So it is conceivable that these instruments can be either early prototypes of future GW detectors, or instruments specifically built for geophysical observations.…”

Section: Sensitivity Of Low-frequency Gravity Strainmetersmentioning

confidence: 99%

“…As explained by Harms et al (2013), terrestrial gravity noise is expected to pose sensitivity limitations at a level 10 −15 Hz −1/2 at 0.1 Hz mainly due to atmospheric infrasound, and possibly also seismic fields (depending on the instrument site). It was proposed to use microphone or seismometer arrays to coherently cancel associated gravity fluctuations from the strainmeter data.…”

Section: Downloaded Frommentioning

confidence: 99%

“…Superconducting gravity strainmeters achieve seismic-noise reduction by common-mode suppression by differential readout of test-mass displacements versus a common rigid reference (Moody et al 2002). Laser-interferometric concepts rely on active and passive seismic isolation of suspended test masses (Harms et al 2013). Torsion-bar detectors profit from the mechanical filtering of seismic noise through a potentially very low frequency torsion resonance (Ando et al 2001).…”

Section: Sensitivity Of Low-frequency Gravity Strainmetersmentioning

confidence: 99%

“…Measurements of such weak gravity transients are masked by a foreground of seismic noise (Berger et al 2004;Brown et al 2014), which is of the order of 100 nm s −2 between 0.1 Hz and 1 Hz. A novel class of instruments, for example seismically isolated gravity gradiometers (also referred to as gravity strainmeters (Harms et al 2013)), is required to detect these early transients. The past two decades have seen rapid progress in the development of ultra-sensitive gravity strainmeters, mainly driven by Comparison between analytical predictions g th and numerical simulation g num of prompt gravity acceleration perturbations for a shallow strike-slip earthquake and a surface-breaking dip-slip earthquake.…”

Section: Motivationsmentioning

confidence: 99%

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Transient gravity perturbations induced by earthquake rupture

Harms

Ampuero

Barsuglia

et al. 2015

Geophysical Journal International

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S U M M A R YThe static and transient deformations produced by earthquakes cause density perturbations which, in turn, generate immediate, long-range perturbations of the Earth's gravity field. Here, an analytical solution is derived for gravity perturbations produced by a point double-couple source in homogeneous, infinite, non-self-gravitating elastic media. The solution features transient gravity perturbations that occur at any distance from the source between the rupture onset time and the arrival time of seismic P waves, which are of potential interest for real-time earthquake source studies and early warning. An analytical solution for such prompt gravity perturbations is presented in compact form. We show that it approximates adequately the prompt gravity perturbations generated by strike-slip and dip-slip finite fault ruptures in a half-space obtained by numerical simulations based on the spectral element method. Based on the analytical solution, we estimate that the observability of prompt gravity perturbations within 10 s after rupture onset by current instruments is severely challenged by the background microseism noise but may be achieved by high-precision gravity strainmeters currently under development. Our analytical results facilitate parametric studies of the expected prompt gravity signals that could be recorded by gravity strainmeters.

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Section: Sensitivity Of Low-frequency Gravity Strainmetersmentioning

confidence: 99%

Section: Sensitivity Of Low-frequency Gravity Strainmetersmentioning

confidence: 99%

Section: Downloaded Frommentioning

confidence: 99%

Section: Sensitivity Of Low-frequency Gravity Strainmetersmentioning

confidence: 99%

Section: Motivationsmentioning

confidence: 99%

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Transient gravity perturbations induced by earthquake rupture

Harms

Ampuero

Barsuglia

et al. 2015

Geophysical Journal International

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Mechanical Accelerometers

Barone

Giordano

2015

Wiley Encyclopedia of Electrical and Electronics Engineering

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Modern mechanical accelerometers are the result of more than a century of research and development aimed at optimizing the mechanical architectures of classical oscillators (simple pendulum, inverted pendulum, and spring–mass oscillator) as well as careful and effective applications of technology improvements and the introduction of innovative techniques of control and signal readout. A further strong impulse to the development of mechanical accelerometers came from interferometric detectors of gravitational waves, which require accelerometers able to satisfy very stringent specifications on sensitivity, bandwidth, resonance frequency, directivity, compactness, and weight, for applications both in air and in ultrahigh vacuum (UHV) and cryogenics. Among the different mechanical architectures present in literature, the Watt's linkage is one of the most promising ones for the implementation of a new class of mechanical accelerometers (horizontal, vertical, and angular). In this article, a simplified analytical model for a global description of the mechanical behavior and of the sensitivity limits of Watt's linkage‐based mechanical accelerometers is presented and discussed, with respect to methods and techniques for their optimization. State‐of‐the‐art architectures and implementations are also presented, together with selected results of laboratory tests and scientific applications, which show the impressive performances and not yet explored potentialities of this class of mechanical accelerometers.

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