Ground Penetrating Radar (GPR)

MALA GroundExplorer

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The ground penetrating radar (GPR) uses pulses of electromagnetic radiation to image the shallow subsurface up to 30 meters, depending on the subsurface conditions. In areas underlain by water-saturated and/or high conductivity materials such as clays, the imaging depth may be reduced to only a few meters, due to signal absorption and attenuation.

 

A variety of subsurface features can be detected using GPR, such as lithological contacts and erosional surfaces, subterranean cavities, groundwater table, faults and discontinuities, and buried utilities (e.g. pipes, wires,) and engineering works (e.g. foundation rebars, culverts). 

GEAR Lab maintains 3 GPR antennas (160, 450, 750 MHz) that can be mounted on a rough-terrain cart. GEAR Lab also owns a license for the software RadExplorer, which is used to process radargrams prior to interpretation.

Real-Time Kinematic - Global Navigation

Satellite System (RTK-GNSS)

Spectra Precision SP60

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Spatial measurements with up to sub-centimeter precision can be achieved using a pair of Real-Time Kinematic - Global Navigation Satellite System (RTK-GNSS) receivers. Positions of points of interest are measured using a mobile GNSS receiver mounted on a surveying pole, which receives signals from a stationary base GNSS receiver, and the constellation of GNSS satellites which include Navstar GPS, Galileo, GLONASS, and Beidou.

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The RTK-GNSS is particularly useful in obtaining quick and precise topographic profiles and in generating digital surface models (DSM) with fine vertical resolutions. GEAR Lab has also used the RTK-GNSS in mapping coastal boulders, coral microatolls, reef platforms, and marine and fluvial terraces.

Unmanned Aerial Vehicle (Camera Drone)

DJI Phantom 4 Pro

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Unmanned aerial vehicles (UAV) are a widely-used and convenient tool for obtaining detailed aerial photographs of areas covering up to a few square kilometers. Furthermore, by applying stereoscopic techniques and using built-in altimetry, UAVs can be used to obtain high resolution digital surface models.

GEAR Lab maintains and operates a DJI Phantom 4 Pro camera drone, which has been used for geomorphological and land cover mapping of study sites, as well as in mapping of coastal boulders, coral microatolls, and marine terraces. GEAR Lab also owns a license for the digital photogrammetry  software suite Agisoft Metashape, which is used in stitching and georeferencing multiple aerial photographs, and processing point cloud data into digital surface models (DSM) of areas covered by aerial photographs.

Total Station

Nikon Nivo 5C

 

The total station is an equipment designed for precise measurement of angles and distances. It measures vertical and horizontal angles using an electronic theodolite, and measures distances using laser ranging in conjunction with a pole-mounted surveying prism. 

 

GEAR Lab maintains a Nikon Nivo 5C total station, which has been extensively used for topographic profiling and detailed mapping of coastal features such as coral microatolls and marine terraces as applied in sea level change studies.

Coastal Sediment Samplers

Handy Geoslicer (1.5 and 1 m)

 

The handy geoslicer is used to obtain relatively undisturbed vertical sections of sediments, making it possible to observe sedimentary structures that may otherwise are destroyed by other sampling techniques such as auger sampling. The handy geoslicer is composed of two interlocking stainless steel implements: the sampling tray and the shutter plate.

In obtaining geoslicer sections, the sampling plate is first driven into the ground by hammering until the desired depth is reached. After, the shutter plate is also driven along and covering the open side of the sampling tray. Finally, the sampling tray and the shutter plate are extracted from the ground simultaneously using a tripod-mounted pulley. The shutter plate is then removed, revealing the geoslicer section for detailed logging and subsampling.

GEAR Lab maintains 2 sets of 1.5-m and 1 set of 1-m handy geoslicers, as well as a pulley-operated extraction rig. The handy geoslicer has been the workhorse of GEAR Lab's research on coastal sediments as evidence fort past tsunamis and storm surges in the Philippines.

Surveying Altimeter

American Paulin System, TERRA MT-2

 

A barometric-type instrument with a pressure-sensitive element that contracts or expands depending on atmospheric pressure condition; the dial is graduated in units of linear measurement (feet or meters) that indicate differences in elevation.