Analysis of seismo-acoustic emission from ice fracturing events during SIMI�94

Dudko, Yuriy V.

doi:10.1575/1912/4706

Cited by 7 publications

(4 citation statements)

References 37 publications

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“…In that particular case, the vertical polarization can be explained by the origin of this event being in the near-field zone because the source of this particular event was close to the station (less than 300 m). Such polarization in the near-field zone is in agreement with the evaluation of the radiation pattern from the surface tensile fracture opening in ice (Dudko, 1999).…”

Section: Resultssupporting

confidence: 86%

Frost quakes in wetlands in northern Finland during extreme winter weather conditions and related hazard to urban infrastructure

Afonin,

Kozlovskaya,

Moisio

et al. 2024

The Cryosphere

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Abstract. The paper reports the first results of an experiment in northern Finland during winter 2022–2023 that aimed at studying seismic events caused by seasonal freezing in the so-called critical zone (CZ) of the Earth. These events have attracted public attention recently, as multiple reports about them from local inhabitants in Arctic and sub-Arctic areas appeared on social networks. To make an instrumental study of such events, to reveal the relationship between their occurrence and winter weather conditions, and to evaluate the possible hazard, we installed two high-resolution seismic arrays with co-located soil temperature stations at two sites in Finland, one of them being in the city of Oulu in the sub-Arctic area (65.04° N, 25.61° E) and the other one above the polar circle in the municipality of Sodankylä (67.36° N, 26.63° E). The equipment recorded continuous seismic and soil temperature data during November 2022–April 2023. Based on reports from the inhabitants of Talvikangas (Oulu) about the ground shaking and unusual noises on 6 January 2023 and their observations of new fractures on the roads there, we selected the time interval for the identification of frost quakes that originated during that day from continuous seismic records in Talvikangas and in Sodankylä. During the selected time interval, the extremely rapid air temperature drops of about −1.4 °C h−1 in Talvikangas and −0.88 °C h−1 in Sodankylä were observed. We identified and located two types of seismic events – namely, frost quakes with frequencies of about 10–20 Hz, with waveforms like those of tectonic events, and irregularly shaped frost tremors with frequencies of about 120–180 Hz. The sources of frost quakes in Talvikangas are mainly located on irrigated wetland, while in Sodankylä, about 50 % of registered frost quakes were caused by ice fracturing on the Kitinen River. However, several relatively strong events, with their origin in the wetlands, were also recorded. A significant number of sources of frost tremors are confined to wetland areas cut by irrigation channels and to roads cleaned from snow during winter both in Talvikangas and in Sodankylä. We calculated ground accelerations and ground velocities for the strongest events from both groups and compared them to equivalent properties of other seismic signals, like distant local earthquakes in the area, mining production blasts, and cargo train vibration. Our study shows that high-frequency frost tremors corresponding to surface fracture opening in the uppermost frozen surface layer of a thickness of up to 5 cm can directly damage infrastructure objects like roads and basements of buildings. Surface waves, produced by frost quakes and propagating inside the shallow soil layer, have large enough ground accelerations at epicentral distances of hundreds of metres. Therefore, frost quakes should be considered a phenomenon that can potentially damage infrastructures, and they have to be taken into account in seismic hazard assessments. Our research is the first instrumental study of seismic events originating from wetland areas. These events occur as a result of the interaction between the uppermost layer of the solid Earth's CZ and atmosphere processes that deserves further study.

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Section: Resultssupporting

confidence: 86%

Frost quakes in wetlands in northern Finland during extreme winter weather conditions and related hazard to urban infrastructure

Afonin,

Kozlovskaya,

Moisio

et al. 2024

The Cryosphere

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“…Phases displaying reverse dispersion are a prominent component of floating ice-sheet seismology, and are observed commonly in lake ice, sea ice and ice shelves (e.g. Ewing and Crary, 1934; Press and Ewing, 1951; Hunkins, 1960; Hatherton and Evison, 1962; Xie and Farmer, 1994; Dudko, 1999, and references therein). A parsimonious explanation of the reverse-dispersed phases seen in the diurnal seismicity cycle is that they are generated when the superimposed ice lid imparts a vertical impulse to the ice-shelf immediately below as it undergoes thermal fracture (e.g.…”

Section: Diurnal Seismicity Waveformsmentioning

confidence: 99%

Diurnal seismicity cycle linked to subsurface melting on an ice shelf

MacAyeal

Banwell

Okal³

et al. 2018

Ann. Glaciol.

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Seismograms acquired on the McMurdo Ice Shelf, Antarctica, during an Austral summer melt season (November 2016–January 2017) reveal a diurnal cycle of seismicity, consisting of hundreds of thousands of small ice quakes limited to a 6–12 hour period during the evening, in an area where there is substantial subsurface melting. This cycle is explained by thermally induced bending and fracture of a frozen surface superimposed on a subsurface slush/water layer that is supported by solar radiation penetration and absorption. A simple, one-dimensional model of heat transfer driven by observed surface air temperature and shortwave absorption reproduces the presence and absence (as daily weather dictated) of the observed diurnal seismicity cycle. Seismic event statistics comparing event occurrence with amplitude suggest that the events are generated in a fractured medium featuring relatively low stresses, as is consistent with a frozen surface superimposed on subsurface slush. Waveforms of the icequakes are consistent with hydroacoustic phases at frequency $ {\bf \gt} \bf 75\,{\bf Hz}$ and flexural-gravity waves at frequency $ \bf {\bf \lt}25\,{\bf Hz}$. Our results suggest that seismic observation may prove useful in monitoring subsurface melting in a manner that complements other ground-based methods as well as remote sensing.

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“…Ocean surface waves are the most common mechanism for generating waves in pack ice, in particular close to the ice edge (Squire, 2007), but long infra-gravity waves penetrate thousands of kilometers inside the ice cover (Squire and others, 2009; Wadhams and Doble, 2009). In addition to externally forced motion, other types of waves are also observed in the pack due to its kinematics, including fracturing, ridge build-up and ice floe/floe collision (Yang and Giellis, 1994; Dudko, 1999).…”

Section: Introductionmentioning

confidence: 99%

“…These impulsive ‘ice transients’ are ubiquitous and can be investigated in detail using compact seismic arrays, with limited (up to kilometers) apertures. Crack lengths of a few meters, associated with sub-millimeter displacements, have been reported (Dudko, 1999). These high-frequency events are very different from the large-scale shear motions localized along leads, which accommodate most sea-ice brittle deformation.…”

Section: Introductionmentioning

confidence: 99%

Low-frequency bursts of horizontally polarized waves in the Arctic sea-ice cover

et al. 2011

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ABSTRACT. We report the detection of bursts of low-frequency waves, typically f = 0.025 Hz, on horizontal channels of broadband seismometers deployed on the Arctic sea-ice cover during the DAMOCLES (Developing Arctic Modeling and Observing Capabilities for Long-term Environmental Studies) experiment in spring 2007. These bursts have amplitudes well above the ambient ice swell and a lower frequency content. Their typical duration is of the order of minutes. They occur at irregular times, with periods of relative quietness alternating with periods of strong activity. A significant correlation between the rate of burst occurrences and the ice-cover deformation at the ∼400 km scale centered on the seismic network suggests that these bursts are caused by remote, episodic deformation involving shearing across regional-scale leads. This observation opens the possibility of complementing satellite measurements of ice-cover deformation, by providing a much more precise temporal sampling, hence a better characterization of the processes involved during these deformation events.

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Analysis of seismo-acoustic emission from ice fracturing events during SIMI�94

Cited by 7 publications

References 37 publications

Frost quakes in wetlands in northern Finland during extreme winter weather conditions and related hazard to urban infrastructure

Frost quakes in wetlands in northern Finland during extreme winter weather conditions and related hazard to urban infrastructure

Diurnal seismicity cycle linked to subsurface melting on an ice shelf

Low-frequency bursts of horizontally polarized waves in the Arctic sea-ice cover

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