Seismic Activity Data Collection on the Ocean Floor

Sponsored Article
Unlike neighbouring Japan, earthquake activity is infrequent in the peninsula area of South Korea, and those that do occur tend to be low in intensity. Typically, earthquakes in this region measure between 2.0 and 5.0 on the Richter scale[1]. The record for the quake with the highest magnitude on the Korean Peninsula stood for some time, recorded at 5.3 in 1980. This was recently overtaken by a 5.8 magnitude tremor in Gyeongju in 2016 and a 5.4 magnitude tremor in Pohang, followed soon after by a 4.8 magnitude aftershock tremor. Data on these events is collected using the existing seismological... (read more)
2019-08-06 08:30:32

Visited for You

  Ocean Business   From 31 March to 2 April, Ocean Business and Ocean Careers took centre stage at the National Oceanography Centre in Southampton (UK), followed by Offshore Survey from 1 April.   However, on 30 March there was already much ongoing activity; stands were set up, delegates arrived. Hydro international was invited to join RESON, before the opening of the show, to see the RESON sonars in action. Surveying the harbour of Southampton on board of Southampton's Port Management Protector, a few remarkable features were discovered that even the regular harbour surveyors had not discovered before! In a... (read more)
2009-05-12 12:00:00

Acoustic Seabed Classification

Integration into hydrographic survey programmes
Acoustic seabed classification is rapidly gaining acceptance as a useful tool amongst the world's ocean community. Commercial classification products can measure acoustic diversity in the surficial seafloor zone and produce thematic maps of the resulting acoustic classes. Hydrographic services throughout the world routinely conduct bathymetric surveys using single beam sounders and multibeam sonar. These operations are ideal candidates to serve as 'surveys of opportunity' for acquisition of acoustic classification information. The hydrographic office itself gains significantly better seafloor information for charting purposes, with the added benefit that the ocean community outside hydrography gains a new capability to manage the delicate... (read more)
2008-01-01 01:00:00

Joining Up Land and Sea

UKHO/UCL Vertical Offshore Reference Frame
Development of a vertical surface separation model will allow easier assimilation of land and maritime data sources, resulting in seamless vertical data. The future possibilities of having data that can be easily output on different vertical datums cannot be overstated. The imminent arrival of the United Kingdom Hydrographic Office Vertical Offshore Reference Frame (VORF) may meet this challenge. For over 150 years traditional bathymetric and topographic measurements have been collected independently to serve different purposes. Today depth and height data tend to be referred to different vertical datums, creating inconsistency across the land-sea interface. Depth datums in particular are usually... (read more)
2008-01-01 01:00:00

Integrating Offshore Tide Model Output with Onshore Observations

Improving Correctors to Hydrographic Survey Soundings
The National Oceanic and Atmospheric Administration (NOAA) develops tide correctors for reducing hydrographic survey soundings to Chart Datum by using the Tidal Constituent and Residual Interpolation (TCARI) software to interpolate harmonic constituents (HCs), tidal datum elevation relationships and water level residuals from observations. Due to the complex tidal regime and limited coastal observations in the Bering Sea, the error associated with tide correctors generated from the TCARI interpolation exceed the 45cm National Ocean Service standard in some offshore areas. In an effort to develop a higher quality tide corrector, a method of blending offshore HCs from high-resolution tide models and... (read more)
2015-08-27 02:18:45

Survey is Means for Preventing Damage to Nature

Hydro International Interviews Andy Hill
Andy Hill is key-note speaker at OI 10 in London and convening the Hydrography and Geophysics track of the conference. As Marine Geohazards Technical Authority at BP he states that the company undertakes hydrographic surveys to ensure safety, integrety and protection of the environment in all its operations. Mr. Hill, as convener of the Hydrography and Geophysics theme at the OI Conference in London this year, can you tell us about the scope of the sessions?We have split the theme up into three separate sections: we will have a session on AUV applications and developments, a series of papers on... (read more)
2010-03-02 01:47:17

ALB Evaluation for NOAA Charting Requirements

Creating Acceptance Test for Airborne Lidar Bathymetry Data Application to NOAA Charts in Shallow Waters
The National Oceanic and Atmospheric Administration (NOAA) acquires hydrographic data around the coasts of the US and its territories using in-house surveys and contracting resources. Hydrographic data are primarily collected using sonar systems, while a small percent is acquired via Airborne Lidar Bathymetry (ALB) for nearshore areas. NOAA has an ongoing requirement, as per the Coast and Geodetic Survey Act of 1947, to survey nearshore areas as part of its coastal mapping activities, including updating nautical charts, creating hydrodynamic models and supporting coastal planning and habitat mapping. NOAA has initiated a project to investigate the potential use of ALB data... (read more)
2013-12-04 04:38:42

Identification of the ­Wreck of the U.S.C.S.S. ­Robert J. Walker

From 21 to 24 June 2013, a NOAA team from the Office of Coast Survey (OCS) and the Office of National Marine Sanctuaries (ONMS) conducted a joint mission to explore a shipwreck off the coast of New Jersey near Absecon Inlet and Atlantic City. That wreck has proved to be the oldest known wreck of a hydrographic survey ship yet found, Robert J. Walker, a US Coast Survey ship wrecked in 1860 with loss of twenty crewmembers, whose tragic story resonates within NOAA to this day. The NOAA Ship Thomas Jefferson, performing hydrographic surveys off the New Jersey coast in... (read more)
2013-12-04 05:01:20

Surveying the River Dee

The challenges of a mission (im)possible
In April 2004 an unusual vessel, the Afon Dyfwydwy made its first transit down the River Dee carrying the wings for the new Airbus A380. This was the culmination of many years of work for a number of companies, including Pelorus Surveys, and a proud moment for all involved. The Airbus factory at Broughton produces the wings for the Airbus range of aircraft and, to date, these have all been transported to the assembly facility in Toulouse, France using a modified Airbus flying from Broughton. However, each of the wings for the A380 is 48 metres long, 14 metres wide... (read more)
2008-01-01 01:00:00

High-resolution Magnetic Target Survey

Harnessing the power of three-axis total-field magnetic gradient
Magnetic surveying is a common methodology for small-object detection applications such as UXO clearance, pipeline location and archaeology. Now gradiometers using Overhauser technology are doing the job faster and better by directly measuring the analytic signal - a high-resolution data form that is ideal for resolving small magnetic features and eliminating the unwanted effects of geology and solar interference. Magnetometers have long been used to locate small, buried ferrometallic objects in all varieties of marine environments. Quantum total-magnetic-field sensors based on the well-known proton or the more recent and powerful Overhauser technology have made the acquisition of stable, good quality,... (read more)
2008-01-01 01:00:00
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