The IMS hydroacoustic network do detects signals from underwater explosions, military activities, anti-submarine exercises, marine seismic surveys and blast fishing. This study investigated access and usage to IMS hydroacoustic data. The population of the study was State Parties in the Africa region. Source of data was primary and were collected through structured questionnaire which was...
The National Data Centre (NDC) in Ghana is part of a global network of capacity building under the auspices of 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...
Three-dimensional acoustic propagation in the open ocean for low frequency sound is an observed phenomenon (Heaney and Murray, JASA 2008), and is known to lead to biases in the localisation of long-range sources (Munk et. al., JASA, 1988). In this paper, a high-fidelity fully 3D global acoustic Parabolic Equation model is applied to the problem to demonstrate the impact of 3D acoustic...
Noise levels generated in the Peruvian marine environment resulting from the application of hydroacoustic technology in the development of civil anthropogenic activities are aimed to the rational use of fishery resources, exploitation of minerals (oil and gas exploration), infrastructure construction and maritime traffic. Main applications are: Fishery resources surveying, began in Peru...
While deep water ambient sound level increases have been documented in the eastern North Pacific Ocean over the past 60 years, it remains unclear whether this trend increasing is observed globally. Data from the Comprehensive Nuclear-Test-Ban Treaty Organization International Monitoring System (CTBTO IMS) was used to examine the rate and direction of low frequency change over the past decade...
the government of burkina faso throught the ministry of foreign affairs in a billateral agreement with the PTS for CTBTO established a NDC in Burkina with the aim of monitoring the testing of nuclear explosions. Seismic, hydro acoustic, radionucleide and infrasound methods are used for the monitoring. The NDC was commissioned in February 2010 and currently has nearly 5 technicians who treats...
Ulleungdo is an island located in the East sea of Korea. Korea Institute Geoscience and Mineral Resources (KIGAM) has operated a seismic array station called ULDAR composed of four CMG-40T sensors and four Q330 digitizers since December, 2007. This study is about the T-wave recorded by ULDAR. The ULDAR recorded various noises and signals different from those recorded at inland stations. We...
Measurements of ocean sound ocean have been made in many locations at many times since hydrophones were first deployed in the 1950s, and measurements in the North Pacific Ocean and some other regions show that sound has increased over this period. This increase has significant implications for organisms that live in the ocean and use sound for life functions. Much ocean acoustic data are...
The IMS uses hydroacoustic, seismic, infrasound and radionuclide technologies to monitor compliance with the CTBT. These technologies, together with data/products of the IDC, have potential civil/scientific applications which benefit states and the scientific community. IMS hydrophone and T-phase stations are able to monitor natural geophysical events (underwater seismicity and volcanism) and...
A study was conducted to review advances in undersea technology with an emphasis on the applicability of a modularized approach to the next generation IMS Hydroacoustic Stations. The primary objective of the study was improving station maintainability. In the past 10 to 20 years, significant technological developments in undersea connectivity have been made driven by the emergence of ocean...
Comoros Islands, roughly in between (11-13 degrees) Latitudes and (43-45 degrees) Longitudes, are located at the Western Indian Ocean side, Along the Northern end of the Mozambique Channel, separating Madagascar from Southeastern Africa . The Indian Ocean region, mostly affected by seismic activities, experienced Hazards and effects of the most damaging wide Tsunami from under water...
Offshore observations make it possible to detect tsunamis in advance prior to their arrivals at the shoreline. For this purpose, bottom pressure gauges are traditionally used. However, in near- or intermediate-fields, ocean bottom pressure records usually exhibit a complicated interference of signals related not only to gravitational wave, but also to hydro-acoustic and seismic waves. Network...
We estimated the detonation depth and net explosive weight for a very shallow underwater explosion using cutoff frequencies and spectral analysis of seismic and hydroacoustic waves. With detonation depth and a bubble pulse the net explosive weight for a shallow underwater explosion could simply be determined. The ray trace modeling confirms the detonation depth as a source of the...
Technology advancements in Ocean science observatories particularly in the area of power and data transport and wet matable power and data connection, provide new opportunity for IMS and other similar systems to be upgraded and maintained. An example of a modern operational observatory is the Regional Scale Nodes (RSN) observatory. The system is currently operational and sending real time data...
DONET 1 and DONET 2 are ocean floor observatories designed for real time earthquake and tsunami warning. They include 51 observation points to cover the Nankai trough seismogenic zone SW in Japan. Their observation capability is based on a variety of sensors, such as accelerometer, broadband seismometer, pressure gauges, thermometers and ocean floor hydrophones. Although their construction is...
In our research program, a project to develop a long cruising autonomous underwater vehicle (AUV) is planned. Researches to realize communication with such AUV using time reversal have been conducted. By time reversal, multipath waves are converged so that signal-to-noise ratio (SNR) is improved and intersymbol interferences (ISI) are removed. Recently, communication at data rates of 100 and...
In 2013 and 2014, the University of Washington deployed RSN (Regional Scale Nodes), a state-of-the-art cabled ocean observatory. RSN was designed and constructed by the Applied Physics Lab-UW for a 25 year service life. Powered from shore by an 860 km backbone of high-bandwidth, telecom grade electro-optical cable, RSN supports 14 seafloor instrument platforms operating at depths of 80 to 2900...
The Japan Trench, off northeast Japan, is one of the most destructive tectonic plate boundaries. The 2011 Tohoku earthquake (Mw9.0) generated there huge tsunamis that caused severe destruction along the Pacific coastline. A seafloor cabled system with 3 seismometers and 2 tsunami gages had been working above the rupture area since 1996. The system recorded the seismic waves, and the two gages...
When using a hydroacoustic array to determine the bearing of a source, errors in the sensor positions severely reduce the accuracy of any bearing measurements. This issue is particularly problematic for three sensor arrays, designed to work in two dimensions, because of the lack of redundancy built into the array. This paper presents a method for correcting errors in sensor positions. It is...
The requirement for essential maintenance to be carried out on the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) hydrophones means that data from some of these stations may be unavailable for substantial periods of time. In this study we examine the possibility of using seismometer stations located on nearby islands as temporary replacements. To do this, hydrophone station...
