Sediment core sampling using the Vibrocore
In response to an increasing demand for deep sediment core sampling (vibrocoring) in support of marine licences for dredging operations and coastal development projects, we have invested in a small vibrocorer. At a fraction of the cost to deploy and operate when compared to most other similar sampling methods, the vibrocorer is the ideal tool for taking sediment cores for contaminant or granulometric analyses in ports, harbours, estuarine and freshwater environments.
The unit is small and compact and purpose designed for the collection of aquatic sediment cores from relatively small vessels in waters of up to 30 m deep. It is usually deployed from our 7.9 m catamaran Coastal Surveyor, but can be deployed from significantly smaller vessels with an appropriate davit.
The vibrocorer can obtain sediment cores of up to 4 m long and 3 inches (76mm) in diameter from unconsolidated sediments. It works by vibrating the entire core tube at such a high frequency that the sediment becomes thixotropic causing the core tube to sink into the sediment. Further advancement occurs for the length of the core tube or until dry, compacted, or consolidated material is reached. In practice this means that the vibrocorer does not result in core compression and will take extremely high quality samples in mud and sandy sediments, but will not sample gravels to any depth.