Recovering and monitoring the thickness, density, and elastic properties of sea ice from seismic noise recorded in Svalbard

Abstract

Abstract. Due to global warming, the decline in the Arctic sea ice has been accelerating over the last 4 decades, with a rate that was not anticipated by climate models. To improve these models, there is the need to rely on comprehensive field data. Seismic methods are known for their potential to estimate sea-ice thickness and mechanical properties with very good accuracy. However, with the hostile environment and logistical difficulties imposed by the polar regions, seismic studies have remained rare. Due to the rapid technological and methodological progress of the last decade, there has been a recent reconsideration of such approaches. This paper introduces a methodological approach for passive monitoring of both sea-ice thickness and mechanical properties. To demonstrate this concept, we use data from a seismic experiment where an array of 247 geophones was deployed on sea ice in a fjord at Svalbard, between 1 and 24 March 2019. From the continuous recording of the ambient seismic field, the empirical Green function of the seismic waves guided in the ice layer was recovered via the so-called “noise correlation function”. Using specific array processing, the multi-modal dispersion curves of the ice layer were calculated from the noise correlation function, and then inverted for the thickness and elastic properties of the sea ice via Bayesian inference. The evolution of sea-ice properties was monitored for 24 d, and values are consistent with the literature, as well as with measurements made directly in the field.

Analysis of microseismicity in sea ice with deep learning and Bayesian inference: application to high-resolution thickness monitoring

“…7b, where the inverted thicknesses are represented versus time. On average, the thickness increased by about 15 cm, which is consistent with the increase reported in Serripierri et al (2022), but dispersion is more significant. This is because, in the present paper, ice thickness is evaluated from all directions along the shoreline and covers a much larger range of distances from the stations (from 5 to 1000 m) than in Serripierri et al (2022), where it is evaluated along two lines of receivers oriented north-south and east-west, with both lines having a length of 50 m. It is noteworthy that thickness estimates using only icequakes that originate from the same region and at a similar date have a significantly reduced dispersion that is consistent with the standard deviation of each individual inversion, as shown in Fig.…”

“…In the present study, using a constant value for these parameters is, however, a valid assumption, since these have been shown to remain constant around E = 3.8 GPa and ν = 0.28, during the 27 d of deployment (Serripierri et al, 2022).…”

“…However, by making use of the horizontal-displacement components, it will be possible to also recover and monitor Young's modulus and Poisson's ratio, instead of using a constant value. As demonstrated in Serripierri et al (2022), these parameters can be constrained by exploiting the waveforms of the other two guided modes, QS 0 and SH 0 , for which polarization is on the horizontal-displacement components. This could be useful regarding drifting pack ice for long-term monitoring.…”

“…With the miniaturization of electronic components, the rapid progress in terms of battery life and the era of seismic-noise interferometry (Shapiro and Campillo, 2004;Sabra et al, 2005), it has become possible to collect data without the need of active, human-controlled sources and then to process them remotely (Marsan et al, 2019). Therefore, over the past decade, there has been a renewed interest in seismic methods as a complementary means of monitoring the thickness, density and elastic properties of sea ice (Marsan et al, 2012;Moreau et al, 2020a, b;Romeyn et al, 2021;Serripierri et al, 2022).…”

Arctic-Type Seismoacoustic Waveguide: Theoretical Foundations and Experimental Results

“…Another more reasonable approach is to use a single sensor mounted on the ice sheet, which allows measuring the seismoacoustic wavefield over a wide frequency range (0.03-1000 Hz), capturing both seismic and hydroacoustic frequency ranges. In recent years, this new scientific trend of placing sensors directly on the ice surface has been actively developed in seismics [11][12][13]. In addition, it should be noted that in recent decades, new technical solutions have been proposed that allow organizing long-term observations on ice fields in the Arctic.…”