Measurement of the Earth tides with a MEMS gravimeter

Middlemiss, Richard; Samarelli, Antonio; Paul, Douglas J.; Hough, J.; Rowan, S.; Hammond, G.

doi:10.1038/nature17397

Cited by 278 publications

(206 citation statements)

References 33 publications

(18 reference statements)

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“…The presented concepts find general relevance to other nonlinear systems in both quantum and classical domains. Besides the fundamental advance reported here, phononic frequency combs also find applications to accurate MEMS/NEMS resonant sensors adapted for stable long duration measurements [19][20], engineering phase-coherent phonon lasers [21], phonon computing [22][23], pulse train mediated ultrasonic imaging and fundamental investigations of nonlinear phononics [24]. Further, the combination of both optical and phononic frequency combs can also enable the extension of metrology link between optical frequencies to sub-Hz frequencies.…”

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confidence: 72%

Phononic Frequency Comb via Intrinsic Three-Wave Mixing

2017

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A frequency comb consists of a series of equally spaced discrete frequencies. In recent years, optical frequency combs [1][2][3][4][5][6][7][8] have emerged as a potential toolset spanning diverse applications ranging from frequency metrology [1-4] to molecular fingerprinting [8]. Specifically the ability to precisely define the frequency spacing between frequency markers and align these measurements with microwave sources through the comb generation process has led to a number of physical measurements [4] requiring very high accuracy including the observation of gravitational waves [9].Optical frequency combs have been generated by using the comb-like mode structure of modelocked lasers and more recently through the interaction of continuous-waver lasers with high Q toroidal optical microresonators mediated via the Kerr non-linearity [10].Despite the analogies between phonons and photons, a direct analogue for an optical comb in the phononic domain has not been observed and comb generation process is thought to be largely limited by the nonlinear dispersion relations of phonons. However, theoretical work [11] has recently demonstrated the possibility for generation of frequency combs in a phononic system represented by Fermi-Pasta-Ulam α (FPU-α) chains [15] where the dispersion relationship does not play a role. In this letter, we report the first experimental confirmation of a phononic frequency comb in a microfabricated structure bearing similar traits predicted by numerical simulations performed on a FPU-α chain [11]. Additionally, our resonator also captures the onset of Duffing nonlinear mechanism [12][13][14] and its interference with the nominal phononic comb.The non-linear three wave mixing mechanism resulting in the generation of frequency combs is theoretically facilitated through the excitation of non-linear resonances of various orders.Specifically, in Direct Nonlinear Resonance (DNR) as termed in [11], the interaction between the eigenmode and driven phonon mode in a non-linear lattice results in the formation of equi-spaced spectral lines at a characteristic frequency ∆ set by the drive frequency and the intrinsic phonon mode frequencies. Mathematically, the DNR phenomenon can be modelled through the coupled dynamics. Figure 1A) upon the drive level crossing a specific threshold value. Here, the displacement profile corresponding to the sub-harmonic mode can be conceived as a pre-stressed framework for the level of coupling between drive frequency and intrinsic resonance mode ( Figure 1B). That being said, the propensity for comb generation is higher at the antinodes of sub-harmonic mode. Additionally, figure 1b1 provides an evidence for the phase coherency of equidistant comb lines. In this letter, we systematically report the experimental results carried out in the extensional resonator based test bed to understand the frequency comb generation and discuss the opportunities for active tuning of comb structure.The drive amplitude dependence on the phononic comb for an off-resonant drive frequenc...

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confidence: 72%

Phononic Frequency Comb via Intrinsic Three-Wave Mixing

2017

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“…Although the equipment of RPASs can be lost or damaged by the volcanic activities, the operator can safely stay in a remote place. Various sensors can be mounted on an RPAS to monitor volcanic activities, including topography, land cover, heat, gas composition and even gravity field (Saiki and Ohba, 2010;Deurloo et al, 2012;Astuti et al, 2009;Middlemiss et al, 2016). The photogrammetric approach used to obtain topographic data is widely applied because RGB camera sensors are small enough to be mounted on a small aircraft.…”

Section: Volcanic Activitymentioning

confidence: 99%

Review article: the use of remotely piloted aircraft systems (RPASs) for natural hazards monitoring and management

Giordan

Hayakawa

Nex

et al. 2018

Nat. Hazards Earth Syst. Sci.

140

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Abstract. The number of scientific studies that consider possible applications of remotely piloted aircraft systems (RPASs) for the management of natural hazards effects and the identification of occurred damages strongly increased in the last decade. Nowadays, in the scientific community, the use of these systems is not a novelty, but a deeper analysis of the literature shows a lack of codified complex methodologies that can be used not only for scientific experiments but also for normal codified emergency operations. RPASs can acquire on-demand ultra-high-resolution images that can be used for the identification of active processes such as landslides or volcanic activities but can also define the effects of earthquakes, wildfires and floods. In this paper, we present a review of published literature that describes experimental methodologies developed for the study and monitoring of natural hazards. IntroductionIn the last three decades, the number of natural disasters showed a positive trend with an increase in the number of affected populations. Disasters not only affected the poor and characteristically more vulnerable countries but also those thought to be better protected. The Annual Disaster Statistical Review describes recent impacts of natural disasters on the population and reports 342 naturally triggered disasters in 2016 (Guha-Sapir et al., 2017). This is less than the annual average disaster frequency observed from 2006 to 2015 (376.4 events). However, natural disasters are still responsible for a high number of casualties (8733 death). In the period 2006-2015, the average number of causalities caused annually by natural disasters is 69 827. In 2016, hydrological disasters (177) had the largest share in natural disaster occurrence (51.8 %), followed by meteorological disasters (96; 28.1 %), climatological disasters (38; 11.1 %) and geophysical disasters (31; 9.1 %) (Guha-Sapir et al., 2017). To face these disasters, one of the most important solutions is the use of systems able to provide an adequate level of information for correctly understanding these events and their evolution. In this context, surveying and monitoring natural hazards gained importance. In particular, during the emergency phase it is very important to evaluate and control the phenomenon of evolution, preferably operating in near real time or real time, and consequently, use this information for a better risk assessment scenario. The available acquired data must be processed rapidly to support the emergency services and decision makers.Recently, the use of remote sensing (satellite and airborne platform) in the field of natural hazards and disasters has become common, also supported by the increase in geospatial technologies and the ability to provide and process up-to-date imagery (Joyce et al., 2009;Tarolli, 2014). Remotely sensed data play an integral role in predicting hazard events such as floods and landslides, subsidence events and other ground instabilities. Because of their acquisition mode and capabilPublished by Copern...

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“…Further work is warranted to refine the tide-quake timing correlation analysis of these, and other episodes, and to explore in more detail the spatio-temporal evolution of seismicity, stresses and strains, and their properties and relationships to the structural and geometrical properties of the volcanoes, stress fields and diking. The development of a novel, small, low-cost gravimeter technology Middlemiss et al (2016) opens up exciting new prospects for detailed field measurements of gravity, and tidal effects, at volcanoes.…”

Section: Discussionmentioning

confidence: 99%

Volcano Statistics Casebook: Tentative evidence from two real-time analyses for an Earth tide influence on volcano-seismic events

Aspinall¹

2016

SIV

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Based on rapid analyses done in near real-time and in support of scientific advice, I present two cases of prima facie evidence for an earth tide triggering effect on earthquake activity during two volcanic eruption episodes: the first, in relation to large magnitude earthquakes, occurred during August 2014 in the 2014 − 2015 Bárðarbunga-Holuhruan, Iceland, eruption; and the second concerns the timing of VT strings at the Soufrière Hills Volcano, Montserrat. In both cases, statistical testing of the hypothesis that the timings of the seismic events of interest and vertical earth tide phase were not correlated produced probabilities at or below a 5% significance level, suggesting rejection of the hypothesis can be argued. This note outlines the method used for computing earth tide amplitudes at the two volcanoes and the basis and results of the Schuster test for relative phase timings; some comments on the volcanological contexts are added. These findings suggest that further, more formal analysis may be warranted.

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Measurement of the Earth tides with a MEMS gravimeter

Cited by 278 publications

References 33 publications

Phononic Frequency Comb via Intrinsic Three-Wave Mixing

Phononic Frequency Comb via Intrinsic Three-Wave Mixing

Review article: the use of remotely piloted aircraft systems (RPASs) for natural hazards monitoring and management

Volcano Statistics Casebook: Tentative evidence from two real-time analyses for an Earth tide influence on volcano-seismic events

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