Ambient Noise Measurements Research Articles

Integration of site condition information using geographic information system for seismic risk reduction for bridge network

ABSTRACT The seismic risk associated with bridges is a function of the structural vulnerabilities and geological conditions at the bridge site. Geographic Information Systems (GIS) allow to integrate spatial information, such as seismic attenuation or local amplification, into ad-hoc information on the structural characteristics of bridges, thereby increasing knowledge on the seismic risk to which a bridge network is exposed. The aim of this study is to develop a scale of susceptibility to the amplification effect by gathering available data on geographic information system platforms. Among other things, this information includes the thickness of the quaternary deposit and surficial geology, complemented with ambient noise measurements. The region of study, the Saint Lawrence Valley, covers an area measuring 32,000 km2, extending from Quebec City in the north to the US border in the south, and includes approximately 5000 bridges and overpasses. The highest susceptibility levels in the present study are associated with colluvial, alluvial and marine deposits. The proposed susceptibility scale is to be used for a bridge network, and can be integrated into existing seismic evaluation scoring procedures. It contributes to seismic risk reduction for bridge and overpass networks by improving available assessment procedures for prioritising mitigation strategies, emergency planning and post-earthquake interventions.

Subsurface profiling of buried valleys in central alps (northern Italy) using HVSR single-station passive seismic

Active and passive seismic techniques permit to draw images of relevant buried morphologies in mountainous areas. Here we apply the Horizontal-to-Vertical Spectral Ratio (HVSR) passive seismic technique to draw the shape of a buried valley in the core of the Italian Central Alps, at the confluence among the fault-controlled Valtellina, Valchiavenna and Lake Como depressions (“Colico knot”). Twenty-three single-station, ambient-noise measurements were acquired and the site-specific fundamental frequency f0 was obtained by computing the HVSR in the 0.5 Hz to 5 Hz frequency band.Shear wave velocity (Vs)-versus-depth profiles were computed from the inversion of the HVSR curves, under the assumption of a 1D structure. To limit uncertainty, the results were calibrated by comparison with data from two sources: 1) HVSR profiles acquired in a comparable setting in Valtellina, at a site where estimates of Vs for the seismic basement and cover sediments were available; 2) borehole logs which crossed the sediments above the metamorphic bedrock at the Colico knot site. Independent data were used to constrain the best fit of the experimental HVSR peaks at the Colico knot site, in terms of frequency f0 and HVSR amplitude, thus retrieving information about Vs variations related to the bedrock versus sediments unconformity.A SW-NE elongated buried trough, as deep as 150 m below sea-level and up to 2 km wide was drawn from the present-day Adda valley to the Lake Como depression to the South. The morphology of this abandoned and buried course of the Adda river is controlled by active deep-seated gravitational slope deformation along the adjacent mountain slope. The valley was abandoned before the Last Glacial Maximum (latest Pleistocene), plausibly owing to narrowing and uplift induced by deep-seated slope deformation. In fact, the LGM Adda glacier reshaped the valley slopes and the bedrock watershed that separates at present the post-Glacial Adda river course from the paleo-Adda trough.

Whistle characteristics of a newly recorded Indo‐Pacific humpback dolphin (Sousa chinensis) population in waters southwest of Hainan Island, China, differ from other humpback dolphin populations

AbstractIndo‐Pacific humpback dolphins (Sousa chinensis) use whistles to communicate with their conspecifics. Little is known about the acoustic repertoire of Indo‐Pacific humpback dolphins in waters southwest of Hainan Island, a newly recorded population in 2014. In this study, whistles of Hainan humpback dolphin population were collected by using autonomous acoustic recorders. The fundamental frequencies and durations of whistles were in ranges of 0.71–21.35 kHz and 0.06–2.22 s, respectively. Significant intraspecific differences in duration and frequency of whistles were found between the Hainan population and the other geographically neighboring populations (in Chinese waters) or the population in Malaysia waters. Compared with other Sousa species, significant interspecific differences were also observed. Based on clustering analysis, the whistle parameters of neighboring populations were likely similar to each other. Significant differences were found between humpback dolphins in waters southwest of Hainan Island and those dolphins in the neighboring areas, supporting the hypothesis that this population may be independent. Ambient noise measurements in waters of Hainan Island, Zhanjiang, and Sanniang Bay showed that humpback dolphin populations may use whistles with longer duration, lower frequency, and fewer inflection points for more effective communication to adapt to a noisier environment.

Near-surface seismic site characterization using Nakamura-based HVSR technique in the geological complex region of Kangra Valley, northwest Himalaya, India

The two major towns, Kangra and Dharamshala, located in the northwest Himalaya have been a subject of great interest for the first-level microzonation due to their high seismic hazard potential. Tectonically, the region is geologically complex and lying between two major thrusts, i.e., the Main Boundary Thrust (MBT) to the northeast and the Jawalamukhi Thrust (JMT) to the southwest. Therefore, the valley is highly deformed and fractured and has developed several small and major faults longitudinally and transversely. The Kangra town is underlain by the Upper Siwalik Boulder Conglomerates, whereas Dharamshala town by the sandstone, claystone, and mudstone with variable thickness of soft soil cover above the bedrock. These regions faced devastating damage from the 1905 Kangra earthquake (Ms 7.8). So, the ambient noise measurement has been performed using a dense network of 200 free-field stations to measure the fundamental frequency of each site. The analysis revealed a high variation in the typologies of HVSR peaks. The iso-frequency map of the study region indicated a wide variation within and on the peripheries of the basin in a frequency ranging from 0.26 to 12 Hz. Some isolated locations in the north-eastern and north-western parts of the study area also showed a dominance of the high resonance frequency component (12-20 Hz). The study further indicated the amplification factor varying from 1.67 to 7.68, reflecting the impact of impedance contrast between the soft soil and the bedrock.

Crustal thickness and magma storage beneath the Ecuadorian arc

The Northern Andes of Ecuador contain some of the most active volcanic systems in the Andes and extend over a broad region from the Western Cordillera to the Subandean Zone. While it is known that the arc straddles a range of basement compositions, from accreted mafic oceanic terranes in the west to silicic continental terranes in the east, the details of the crustal structure beneath the arc is unclear despite being critical for understanding magmatic and tectonic processes in this portion of the Andes. To gain insight into these processes, we create two 3D models of crustal and upper mantle seismic properties throughout the region. The first highlights the discontinuity structure using receiver functions, which allows for the recovery of crustal thickness beneath the Ecuadorian Andes. We observe a range from ~50 to 65 km under the high elevations, with thicker crust beneath the lower elevation Western Cordillera compared to the higher elevation Eastern Cordillera. This can largely be explained by density variations within the crust that are consistent with observed terranes at the surface, implying these terranes extend to depth. The second model combines our receiver functions with Rayleigh wave dispersion data from ambient noise measurements in a joint inversion to construct a 3-D shear wave velocity model. This model shows several mid-crustal (5–20 km below sea-level) low velocity zones beneath Ecuadorian arc volcanoes that contain a maximum of ~14% melt. These low velocity zones likely represent zones of long-term magma storage in predominantly crystalline reservoirs, consistent with “mush zones”. Furthermore, the depth of the inferred reservoirs below several of the volcanic centers (e.g., Chiles-Cerro Negro and Tungurahua) are in broad agreement with previous geobarometry and geodetic modeling. Our results provide new observations of possible long-term magma reservoirs below other less-studied volcanic systems in the Ecuadorian arc as well, and further contributes to a mounting number of observations indicating long-term magma storage at low melt percentages in the mid-crust beneath active arc systems.

Measurement and analysis of motor-noise in underwater glider

Self-noise is a very disadvantageous factor for underwater glider to observe ocean ambient noise, in which the noise caused by motor is very significant. In order to grasp the characteristics of the motor-noise and its influence on the measurement of ocean ambient noise, a long-term sea trial was conducted in the South China Sea in May 2020, and the self-noise data of underwater glider under different working conditions are obtained. By analyzing the noise level and spectrum level of the motor noise, we obtained the self-noise spectrum characteristics and know that the influence of control motor noise on the noise measurement of head and tail hydrophone is mainly below 5 kHz band, and the influence of full-frequency noise level brought by motor is within 10dB and 5dB respectively. The results lay an important foundation for further analysis of ocean ambient noise measured by underwater glider.

Visualizing how anthropogenic noise affects the Good Environmental Status of the North Sea

The Joint Monitoring Programme for Ambient Noise North Sea (JOMOPANS) aimed to develop a framework for managers, planners and other stakeholders to incorporate the effects of ambient noise in their Good Environmental Status (GES) assessment of the North Sea. This was accomplished by generating spatial maps of the anthropogenic and natural soundscapes, modelled from ambient noise measurements collected around the North Sea by the different member states in 2018 and 2019. We focused on the depth-averaged sound pressure level (SPL) of the one-third octave (base-10) bands between 10 Hz to 20 kHz in one second snapshots, viewed in monthly percentiles. From these data, we can better understand the criteria and noise thresholds necessary to achieve GES in the North Sea. Part of this effort was to develop a GES Tool, which would allow users to view the modelled noise maps by noise type (ship type, weather, etc.), protected areas designated by various EU agencies, and habitats used by soniferous or sound sensitive species. The tool computes and displays areas where there is a large overlap between anthropogenic noise and key marine species. This tool aims to help policy makers evaluate measures and thresholds put forward to achieve GES.

RaspMI: Raspberry Pi Assisted Embedded System for Monitoring and Recording of Seismic Ambient Noise

Recently, the passive seismic techniques based on the microtremor measurements have emerged as an alternative to conventional seismic and geotechnical methods used in engineering seismology and earthquake engineering, especially in the local site effect investigations. These methods are basically based on the recording of seismic ambient noise and analysis of its spectral features. Although these techniques are more practical than traditional seismic methods, the commercial instruments designed for recording the seismic ambient noise are quite expensive. Furthermore, most of these instruments require an external computer for recording and monitoring the data. In this sense, this article intends to present a low-cost and Raspberry Pi single-board microcomputer aided seismic ambient noise recording and monitoring system (RaspMI) as an alternative to the computer aided commercial seismic noise measurement systems. RaspMI is an open-source hardware and software system that is controlled by a graphical user interface developed by using the MonoDevelop cross-platform and C# programming language. This system has many features such as 72 dB dynamic range, 100 Hz sampling frequency, timer recording mode, text and SAC data file format, and latitude, longitude, date and time support with GPS module. RaspMI has subjected to the various tests in terms of the reliability and sensitivity. The obtained results have shown that RaspMI can be used as an alternative instrument for seismic ambient noise measurements.

Ambient Noise Measurements to Constrain the Geological Structure of the Güevéjar Landslide (S Spain)

The reactivation of very large landslides may cause severe damage to society. Its prevention and management requires detailed information on the geometry and structure of these landslides, but the use of standard techniques (boreholes) may be prohibitive from an economic point of view. To overcome these difficulties, geophysical techniques are of special interest because they allow for studying very large areas at a reasonable cost. In this paper, we present a case study wherein the analysis of ambient noise allowed us to produce a model of a large landslide near Granada (southern Spain). The geometry and location of the failure zone, as well as the assessment of the state of involved materials, were estimated by combining two available boreholes and different geophysical techniques (downhole tests and the spectral analysis of ambient noise, horizontal to vertical spectral ratios (HVSR) and the frequency-wavenumber (f-k) methods). The results have allowed us to differentiate between values within the landslide mass with respect to those of stable materials, and to perform for the first time a comprehensive geological model of this unstable mass. Differences were also observed within the landslide mass (earth flow vs. slide zones), which are attributed to differences in the degree of alteration and the disturbance of the internal structure of materials constituting the landslide mass. These results show that techniques based on the measurement of ambient noise are of special interest for studying very large, highly remolded landslide masses.

Site response studies in Peshawar using the Nakamura technique of HVSR

In this study, soil response analysis in the Peshawar district is undertaken to characterize their local effects using experimental ambient noise measurements. The Nakamura HVSR method has been used to estimate the fundamental frequency of the soils at 75 test site locations, using a 3-component tomograph. Validation of the peak frequency of amplification of soils obtained was carried out using pre-, post-, and main-event data of real earthquake records in Peshawar and at excavated test sites. It has been found that the cultivated areas exhibit a large peak of H/V amplification (4) corresponding to resonance frequencies ranging from 1.3 to 2.1 Hz in contrast to hard-rock sites with low amplification. Some hard-rock sites have a thick cover of soil and a large variation in H/V peak amplification corresponding to frequency ranges from 3.3 to 10.5 Hz. The H/V curves for most of the sites result in a single peak of large amplification and could be associated with sharp discontinuities consistent with a large velocity contrast uni-model of a single layer overlying the bedrock. The site responses of the low fundamental frequencies corresponding to large amplitude are observed to enable identifying cultivated areas that form important inputs in the seismic hazard microzonation of the Peshawar district.

Multiple geophysical investigations to characterize massive slope failure deposits: application to the Balta rockslide, Carpathians

SUMMARYOrigins of ancient rockslides in seismic regions can be controversial and must not necessarily be seismic. Certain slope morphologies hint at a possible coseismic development, though further analyses are required to better comprehend their failure history, such as modelling the slope in its pre-failure state and failure development in static and dynamic conditions. To this effect, a geophysical characterization of the landslide body is crucial to estimate the possible failure history of the slope. The Balta rockslide analysed in this paper is located in the seismic region of Vrancea-Buzau, Romanian Carpathian Mountains and presents a deep detachment scarp as well as a massive body of landslide deposits. We applied several geophysical techniques on the landslide body, as well as on the mountain crest above the detachment scarp, in order to characterize the fractured rock material as well as the dimension of failure. Electrical resistivity measurements revealed a possible trend of increasing fragmentation of rockslide material towards the valley bottom, accompanied by increasing soil moisture. Several seismic refraction surveys were performed on the deposits and analysed in form of P-wave refraction tomographies as well as surface waves, allowing to quantify elastic parameters of rock. In addition, a seismic array was installed close to the detachment scarp to analyse the surface wave dispersion properties from seismic ambient noise; the latter was analysed together with a colocated active surface wave analysis survey. Single-station ambient noise measurements completed all over the slope and deposits were used to further reveal impedance contrasts of the fragmented material over in situ rock, representing an important parameter to estimate the depth of the shearing horizon at several locations of the study area. The combined methods allowed the detection of a profound contrast of 70–90 m, supposedly associated with the maximum landslide material thickness. The entirety of geophysical results was used as basis to build up a geomodel of the rockslide, allowing to estimate the geometry and volume of the failed mass, that is, approximately 28.5–33.5 million m3.

Dynamic behavior assessment of public buildings in Syria using non-linear time-history analysis and ambient noise measurements: a case study

This study evaluates the dynamic behavior and performance of vital reinforced concrete (RC) public building [Ministry of Higher Education (MHE)] designed in compliance with the old Syrian (non-seismic) building code. The real non-linear dynamic behavior of the MHE building has been checked by detailed dynamic numerical analyses (finite elements method—FEM) validated by a series of ambient noise measurements carried out on-site. The modeling approach for the thorough 3D dynamic analyses of the (RC) MHE building has been developed to be able to investigate the actual non-linear dynamic performance of widespread range of RC structures, providing the opportunity to set up a reliable detailed methodology to assess the real dynamic performance of the old vital structures designed according to the old Syrian (non-seismic) building code from the new seismic requirements perspective. The results of the frequency analyses, the nonlinear time history, and the experimental measurements have shown an excellent agreement. The study showed that the modeling approach by the FEM is reliable for predicting the actual dynamic behavior of RC structures, but it is very sensitive to the modeling assumptions. Furthermore, the dynamic performance analyses have revealed unsymmetrical behavior of the east–west wings about the Y-axis which could be attributed to the inefficient seismic rehabilitation executed in 2001.

Directional variations of site response in a landslide area using ambient noise analysis via Nakamura’s and polarization-based method

The complexity of the NE Iran region in which the 2014 Nargeschal landslide occurred, increased the necessity of detailed survey on the site response properties of this region. New investigations expanded the set of ambient noise measurements acquired in a previous work on the area affected by mass movement. The outcome of electrical resistivity and geotechnical studies were used to provide a comprehensive model of the landslide in addition to the substratum geology. The ambient noise recordings were analysed using the well-established Nakamura’s method and a recently devised approach based on the analysis of the Rayleigh wave ellipticity to provide more detailed information on site resonance properties characterized by directional variations. The outputs, which were compared with the results of electrical resistivity tomography and geotechnical investigations, showed the better performance of the latter method in terms of stability and reliability of the results. Indeed, it allowed to detect site resonance characteristics that were unrecognizable by the Nakamura’s method. Conclusively, the ambient noise analysis reveals that the directional resonance on different parts are due to the landslide and structural features of the site. The information obtained in this work is relevant for seismic hazard assessment in the study area.

Recurrent rock avalanches progressively dismantle a mountain ridge in Beichuan County, Sichuan, most recently in the 2008 Wenchuan earthquake

Large earthquake-triggered landslides, in particular rock avalanches, can have catastrophic consequences. However, without accelerometer records, the recognition of slopes prone to such failures remains difficult, because slope-specific seismic response depends on many factors including local topography, landforms, structure and internal geology. We address these issues by exploring the case of a rock avalanche of >3 million m3 triggered by the 2008 Mw7.9 Wenchuan earthquake in the Longmen Shan range, China. The failure, denominated Yangjia gully rock avalanche, occurred in Beichuan County (Sichuan Province), one of the areas that suffered the highest shaking intensity and death toll caused by co-seismic landsliding. Even though the Wenchuan earthquake produced tens of large (volume > 1 million m3) rock avalanches, many of which resulted in dangerous landslides, few studies so far have examined the pre-2008 history of the failed slope or reported on the stratigraphic record of mass-movement deposits exposed along local river courses. The presented case of the Yangjia gully rock avalanche shows the importance of such attempts as they provide information on the recurrence of large slope failures and their associated hazards. Our effort stems from recognition, on 2005 satellite imagery, of topography and morphology indicative of a large, apparently pre-historic slope failure and the associated breached landslide dam, both features closely resembling the forms generated in the catastrophic 2008 earthquake. The follow-up reconstruction recognizes an earlier landslide deposit exhumed from beneath the 2008 Yangjia gully rock avalanche by fluvial erosion since May 2008. We infer a seismic trigger also for the pre-2008 rock avalanche based on the following circumstantial evidence: i) the same source area (valley-facing, terminal portion of a flat-topped, elongated mountain ridge) located within one and a half kilometer of the seismically active Beichuan fault; ii) significant directional amplification of ground vibration, sub-parallel to the failed slope direction, detected via ambient noise measurements on the ridge adjacent to the source area of the 2008 rock avalanche and iii) common depositional and textural features of the two landslide deposits. Then, we show how, through consideration of the broader geomorphic and seismo-tectonic contexts, one can gain insight into the spatial and temporal recurrence of catastrophic slope failures in Beichuan County and elsewhere in the Longmen Shan. This insight, combined with local-scale geologic and geomorphologic knowledge, may guide selection of suspect slopes for reconnaissance, wide-area ambient noise investigation aimed at discriminating their relative susceptibility to co-seismic catastrophic failures. We indicate the feasibility of such investigations through the example of this study, which uses 3-component velocimeters designed to register low amplitude ground vibration.

Topographic effects on seismic responses of steep sloped superficially weathered rock: the case of ‘Rocher Noir’ at Boumerdes city in Algeria

Rocks often showed an alteration in their first meters of depth, by the presence of weathered portion through variable thickness. Concentration of building damage near the edge of hard or dense cliff has been observed during a number of earthquakes. The numerical analysis of topographic effects of rocky steep slopes knowingly neglects the stratigraphic effect. In previous studies, it was evoked the fracturing of the upper parts of the site of ‘Rocher Noir’ in Boumerdes City, and the obtained HVSR curves were flat or presenting a peak over 10 Hz, explained by the fact that the metamorphic outcropping is overlaid by sediments. In this paper, interaction between the effects of stratigraphic and topographic amplification of this weathered rocky site is investigated through 1D and 2D numerical models. The goal of these investigations is to provide a better understanding of the potential hazard that is represented by amplified ground motion due to the coupling effect (1D amplification and topographic amplification) and to quantify the weathering effects on topographic amplification. Seismic responses (amplification functions and response spectra) are calculated at representative points located in the upper surface of the rocky model, assumed either hard or weathered. The obtained results show that the presence of a weathered portion on the surface can modify the ground response in the sense of higher amplification, larger bandwidth (modifying of the mode vibration), multiple response spectra peaks and inducing a considerable vertical acceleration component. Ambient noise measurements were conducted, the HVSR results agree well with those obtained by modelling.

Underwater sound to probe sea ice melting in the Arctic during winter

Over a 4-year period between 2015 and 2019, in-situ time series measurements of ocean ambient noise over the frequency range 100 Hz to 10 kHz, by an autonomous passive acoustic monitoring system have been made in the Kongsfjorden, Svalbard, Arctic. We characterize the noise due to sea ice melting during winter (December–January). This unique observation reveals loud noise signatures, of the order of 8 dB higher than the background noise, showing the signature of sea ice melting. Such observations are crucial for monitoring sea ice melting, especially during winter, to understand the recent warming of Arctic waters. The anomalous air temperature due to local atmospheric forcing and warming of ocean temperature in the fjord through ocean tunneling, individually or combinedly, is responsible for such sea ice melting. The cyclonic events in the Arctic are responsible for the anomalous atmospheric and ocean conditions, causing sea ice melting in winter.

Seismic Performance Assessment of an Existing RC Wall Building with Irregular Geometry: A Case-Study of a Hospital in Croatia

Buildings of strategic importance should be able to resist seismic forces in accordance with potential earthquakes that may occur at the location and remain fully operational afterwards. However, many of them were constructed before the modern principles of seismic design were known (especially regarding detailing and ductility), and therefore may be considered substandard. The first step in mitigating the seismic risk of such structures is to assess their seismic performance and, in particular, to identify their structural deficiencies. This study presents a comprehensive methodology for the seismic performance assessment of individual buildings, applied to an existing reinforced concrete (RC) hospital. This building is of an irregular layout, constructed as a structural wall system, and it is located in the seismically active region of Croatia. It includes the assessment of seismic hazards on the location, ambient noise measurements, experimental determination of structural modal parameters, creation of a detailed numerical model calibrated with experimental data, and a seismic performance assessment using various analysis methods. As a result, the building collapse mechanisms were determined and critical structural elements identified, which is the basis for future actions directed to the reduction of its risk (e.g., applications of specific measures for a target retrofit, proposal of evacuation routes and safe places inside the building, etc.).

Imaging the Deep Structures of Los Humeros Geothermal Field, Mexico, Using Three-Component Seismic Noise Beamforming

AbstractWe present a 1D shear-velocity model for Los Humeros geothermal field (Mexico) obtained from three-component beamforming of ambient seismic noise, imaging for the first time the bottom of the sedimentary basement ∼5 km below the volcanic caldera, as well as the brittle-ductile transition at ∼10 km depth. Rayleigh-wave dispersion curves are extracted from ambient seismic noise measurements and inverted using a Markov chain Monte Carlo scheme. The resulting probability density function provides the shear-velocity distribution down to 15 km depth, hence, much deeper than other techniques applied in the area. In the upper 4 km, our model conforms to a profile from local seismicity analysis and matches geological structure inferred from well logs, which validates the methodology. Complementing information from well logs and outcrops at the near surface, discontinuities in the seismic profile can be linked to geological transitions allowing us to infer structural information of the deeper subsurface. By constraining the extent of rocks with brittle behavior and permeability conditions at greater depths, our results are of paramount importance for the future exploitation of the reservoir and provide a basis for the geological and thermodynamic modeling of active superhot geothermal systems, in general.

Imaging Subsurface Structure of an Urban Area Based on Diffuse-Field Theory Concept Using Seismic Ambient Noise

Single station ambient noise measurement in campaign mode has of late gained a huge popularity among geo-scientists. Herein, we present results of ambient vibration analysis, executed in a highly populated urban area covering 47 survey points. The resonance frequency estimates range from 0.5 to 3 Hz, as found from H/V. Taking H/V curve as input for retrieving subsurface information, we deploy diffuse field assumption (DFA) theory. The obtained shear wave velocity from the inversion of H/V curve through DFA approach provides evidence of the complex nature of the subsurface geological structures. Identifying six characteristic 2D cross-sections of the entire area, we attain prevalence of a low-velocity intermediate layer with velocity ranging from 128–192 m/s. On the contrary, a relatively high-velocity layer is also obtained (279–471 m/s) which can be treated as sedimentary deposits (may be for some sites as basin basement). The attained results, when extended to a 3D shear wave profile, tally excellently with estimated frequency distribution and its corresponding links with depth wise strata, accompanied by a topographical profile of the surveyed locations. All findings are comprehensively analyzed and interpreted as a proof of concept of implementation of DFA approach towards retrieving subsurface information.

Ambient Noise Measurement System for the Arctic Region

Ayyadurai, T.; Raguraman, G.; Ashokan, M., and Latha, G., 2020. Ambient noise measurement system for the Arctic region. In: Sheela Nair, L.; Prakash, T.N.; Padmalal, D., and Kumar Seelam, J. (eds.), Oceanic and Coastal Processes of the Indian Seas. Journal of Coastal Research, Special Issue No. 89, pp. 67-70. Coconut Creek (Florida), ISSN 0749-0208.Ambient noise measurements in the polar region are challenging due to the ice-covered environment and very low temperature prevailing in the region. The primary aim of this research work is to design and develop a system capable of associated components to withstand harsh environments, such as the Arctic region. This system consists of a hydrophone, a data acquisition system and a battery pack placed in an indigenously developed underwater pressure casing. While the water depth is 190 m, the noise measurement system is placed at a depth of 30 m. The objective of this work is to record the time series of ocean ambient noise in the Kongsfjorden fjord, Arctic region, covering the seasonal cycle and study the sea ice dynamics and biological noise.