The South American continental shelf and territory is covered by 16 (primary and auxiliary) IMS seismic stations and 1hydroacoustic station. The data from both the hydroacoustic station and seismic stations were used to analyse the two events that occurred in Chile on September 16, 2015 and Ecuador on 16 April, 2016 to assess the efficiency of these stations. This research effort is devoted to...
The advent of deep-sea cabled observing systems and related installation and maintenance requirements has driven the development of new practices and new capabilities in subsea intervention. Since 2006 Ocean Networks Canada and its partners have led innovations that range from modular sensor platform designs to major rebuilds of scientific ROVs and the development of sophisticated instrument...
The National Data Centre (NDC) in Ghana is part of the global network under the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). The Data Centre has technical expertise in the monitoring and verification technologies of the Comprehensive Nuclear-Test-Ban Treaty and provides technical advice and support on issues pertaining to the verification of the Treaty. The main work of the data...
The Nankai Trough area is one of important targets to monitor crustal activities due to the potential of future huge earthquakes and tsunamis. To monitor crustal activities, the Dense Oceanfloor Network system for Earthquakes and Tsunamis (DONET) was installed in rupture areas of the Tonankai/Nankai earthquakes. The installed area has generally low seismicity but slow slip events have...
EMSO (European Multidisciplinary Seafloor and water-column Observatory, www.emso-eu.org) is a European large‐scale distributed Research Infrastructure (RI) with the essential scientific objective of real‐time, long‐term observation of environmental processes related to the interaction between the geosphere, biosphere, and hydrosphere, for multidisciplinary and interdisciplinary investigation...
In 2015, the University of Tokyo deployed 4th seafloor cabled system. It is 2nd cabled system in the off-Sanriku region, the northwest Pacific, and 2nd generation of Internet Protocol (IP) based observatory. We employed standard Transmission Control Protocol/Internet Protocol (TCP/IP) with a speed of 1 Gbps for system control and monitoring, and data transmission. It helps us to reduce cost...
Monitoring of deep-ocean low-frequency sound is challenging, but data have been reported for the Northeast Pacific Ocean and Indian Ocean in a number of recent publications. The CTBTO (Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization) has made available data from their deep-ocean hydro-acoustic stations, so that researchers may examine the existence of trends...
The topic of this paper is algorithm for in situ estimation of the time of arrival, or TOA, which origin are events that have sudden rise of the pressure and may occur in different environments such is air, water or ground. The algorithm is adaptive and based on specific approach that generally means using two-step method. The first is wavelet decomposition of the signal in purpose to rough...
In Japan, S-NET and DONET as real time monitoring system on Earthquakes and Tsunamis have deployed off Tohoku and off Nankai Trough. However, DONET and S-NET are different systems, DONET is a cable system with nodes, on the other hand, and S-NET is an in-line cabled system. DONE i.e. the Dense Ocean-floor Network system for Earthquakes and Tsunamis, and S-NET i.e. Seafloor observation Network...
For absolute measurement of sound in the ocean, and for assurance of stability in long-term monitoring applications, the performance of the measurement system is a crucial factor governing the quality of the measured data. In validating that performance and providing traceability to the measurements, calibration is of vital importance to ensure noise monitoring strategies and in-situ source...
Marine-seismic airguns are used in oil and gas exploration and reservoir monitoring. High-pressure air is rapidly released from submerged airguns, usually towed a few metres from the sea-surface as part of an array that is designed to concentrate sound transmissions vertically downwards. Although the primary use-case of airgun arrays is probing deep into the seabed, the sound they transmit may...
The ocean is nearly transparent for acoustic propagation at low frequencies (< 100Hz), leading to the detection of signals (seismic events, volcanoes and man-made signals) at distances as large as the ocean basin. Observations of a low level source transmission from Guam to Wake Island will be presented. Historically, basin acoustic modeling has neglected out-of-plane effects and has been...
Costa Rica is bordered by the Pacific Ocean on its western side and by the Caribbean Sea on its eastern side, with a total of 1,290 km of coastline. Scientific research and monitoring of physical properties of the ocean in Costa Rica is largely done by the oceanography group of the Department of Physics (DP) at Universidad Nacional. Many of the observations are made with hydroacoustic...
The impact of underwater noise on marine life is a rapidly increasing focus for research, regulatory change, and conservation actions. Digital hydrophone records from Ocean Networks Canada’s cabled observatory systems represent the largest data volume delivered to the science community, supporting research into marine mammal responses to vessel traffic, seasonal use of ocean habitats by...
During December 2016, the Comprehensive Nuclear-Test-Ban-Treaty Organization (CTBTO) re-established the hydro-acoustic station HA04 close to the Crozet Islands in the Indian Ocean as part of the International Monitoring Systemâs (IMS) world-wide, multi-technology sensor network. The station is composed of two triads of hydrophones located to the north and south of Possession Island. High...
In 2016, a study on the design of the next generation cabled hydroacoustic (HA) stations was conducted with the objective of evaluating viable architectures for the sensor package of the underwater system (UWS). The goals of this project were to: (i) improve sustainability by reducing the impact of events that may negatively affect data availability, (ii) facilitate reparability through...
The incorporation of the hydroacoustic station HA04, Crozet Islands, France, into the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) was successfully completed on 29 December 2016. HA04 was Certified and Promoted into Operations on 19 June 2017. Similarly to most other cabled hydroacoustic stations in the IMS, HA04 is comprised of two...
The Dense Ocean-floor Network system for Earthquakes and Tsunamis (DONET) is the real-time seafloor observatory network developed in Japan. In this study, scientific and engineering trends of DONET are addressed, which may contribute to the IMS hydroacoustic network. The large undersea volcano’s eruption took place in the central Mariana Islands in the Pacific Ocean in 2010 and series of...
The presentation will be an overview of the main satellite telemetry solutions dedicated to ocean
data collection programs: Drifting Buoys Cooperation Panel (DBCP), Argo floats program, Ship of
Opportunity (SOT), and other observation programs based on new autonomous vehicles: gliders,
Remotely Operated Vehicle (ROV), Autonomous Underwater Vehicle (AUV), and Unmanned Surface
Vehicle...
Since 2005 a cabled deep-sea infrastructure is operative at 2100 m water depth, 25 km off the port of Catania (Sicily). The infrastructure, under continuous improvement, is the first operative cabled node of the EMSO ERIC, hosting several multidisciplinary observatories built in Collaboration by the Italian Institutions INFN, INGV, CNR, CIBRA and other scientific partners. Hydrophone antennas,...
The Hydroacoustic Monitoring Stations are essentially established to monitor the oceans for underwater explosions. In total, there are 11 stations with six underwater hydrophone stations and five T-phase stations on land in eight countries at entry into force of the CTBT. Despite the fact that all States Parties have open, equal, timely and convenient access to all raw and processed IMS data,...
Permanent seafloor seismic and tsunami observation networks were deployed near the Japan trench and the Nankai trough, Japan. We can monitor seismic waves and tsunamis at the stations in real time and also T-phase signals propagating via the SOFAR channel in the ocean. In this study, we investigated the acoustic source location of the T-phase energy with the travel-time analysis using...
T-phase signals generated by earthquakes with epicentres in or close to ocean areas may be detected after oceanic propagation over distances of tens of thousands of kilometres. Ocean environments are close to being horizontally stratified but lateral variability in water depth or sea-water sound-speed can lead to out-of-plane propagation. This can result in T-phases being detected in locations...
The CTBTO’s International Monitoring System (IMS) includes 6 hydrophone based monitoring stations. During 2016 the Engineering and Development Section within the IMS Division installed the final hydroacoustic station at the Crozet Islands, France.
The weather at Crozet which is situated in the Southern Indian Ocean is such that marine operations have to be carefully planned and can only be...
In 2014, the University of Washington (UW) completed the deployment of the Ocean Observatories Initiative Regional Cabled Array (RCA), a state-of-the-art cabled ocean observatory off the central Oregon coast. The RCA was designed, and constructed by the Applied Physics Lab-UW for a 25-year service life, in conjunction with the UW School of Oceanography. Powered from shore by an 860 km backbone...
On 25/04/2017, the Burkina Faso NDC found an extremely rare event that occurred in the Atlantic Ocean northwest of the Ascension Islands near the West African coast (943 km Monrovia Liberia), a non-seismic zone . What led us to conduct a study on this event in order to know exactly what is happening in the area. This is how, we used seismic and hydroacoustic data and also referred to the IDC...
A hydrophone station in the International Monitoring System (IMS) network can breakdown which can result in reduced monitoring coverage. Seismic data may be used to mitigate this reduction. Here, two examples of how seismic data can be used for the detection, location and characterisation of hydroacoustic signals are presented. In the first of these, signals from a series of underwater...
