Phillips D.A.,UNAVCO |
Oldow J.S.,University of Texas at Dallas |
Walker J.D.,University of Kansas
Eos | Year: 2012
Charting the Future of Terrestrial Laser Scanning in the Earth Sciences and Related Fields; Boulder, Colorado, 17-19 October 2011 A workshop hosted by UNAVCO and funded by the U.S. National Science Foundation (NSF) brought together 80 participants representing a spectrum of research fields with the objective of outlining a strategic vision for the future of terrestrial geodetic imaging as applied to a broad range of research activities at all levels of the community. Earth science investigations increasingly require accurate representation of the Earth surface using three-dimensional data capture, display, and analysis at a centimeter scale to quantitatively characterize and model complex processes. Recognizing this community need, researchers at several universities and UNAVCO established the NSF-funded Interdisciplinary Alliance for Digital Field Data Acquisition and Exploration (INTERFACE) project to support a terrestrial laser scanning (TLS) instrument pool and data collection expertise now based at UNAVCO.
Luttrell K.,U.S. Geological Survey |
Mencin D.,UNAVCO |
Francis O.,University of Luxembourg |
Hurwitz S.,U.S. Geological Survey
Geophysical Research Letters | Year: 2013
Seiche waves in Yellowstone Lake with a ~78-minute period and heights <10 cm act as a load on the solid earth observed by borehole strainmeters with subnanostrain sensitivity throughout the Yellowstone Caldera. The far-field strain induced by the load of the seiche waves calculated with a homogeneous elastic model representing the upper crust is more than an order of magnitude smaller than the measured strain amplitude ~30 km from the lake shore. By contrast, the observed far field strain amplitudes are consistent with the seiche load on a two-layered viscoelastic model representing an elastic upper crust overlying a partially molten body deeper than 3-6 km with Maxwell viscosity less than 1011 Pa s. These strain observations and models provide independent evidence for the presence of partially molten material in the upper crust, consistent with seismic tomography studies that inferred 10%-30% melt fraction in the upper crust. Key Points Strain induced by seiche waves in Yellowstone Lake is observed 30 km away Observed strainfield requires some support from an upper crustal magma reservoir Top of shallowest upper crustal partial melt is at 3 - 6 km depth ©2013. American Geophysical Union. All Rights Reserved.
Fritz H.M.,Georgia Institute of Technology |
Phillips D.A.,UNAVCO |
Okayasu A.,Tokyo University of Marine Science and Technology |
Shimozono T.,Tokyo University of Marine Science and Technology |
And 6 more authors.
Geophysical Research Letters | Year: 2012
On March 11, 2011, a magnitude M w 9.0 earthquake occurred off the coast of Japan's Tohoku region causing catastrophic damage and loss of life. The tsunami flow velocity analysis focused on two survivor videos recorded from building rooftops at Kesennuma Bay along Japan's Sanriku coast. A terrestrial laser scanner was deployed at the locations of the tsunami eyewitness video recordings. The tsunami current velocities through the Kesennuma Bay are determined in a four step process. The LiDAR point clouds are used to calibrate the camera fields of view in real world coordinates. The motion of the camera during recordings was determined. The video images were rectified with direct linear transformation. Finally a cross-correlation based particle image velocimetry analysis was applied to the rectified video images to determine instantaneous tsunami flow velocity fields. The measured maximum tsunami height of 9 m in the Kesennuma Bay narrows were followed by maximum tsunami outflow currents of 11 m/s less than 10 minutes later. © 2012 by the American Geophysical Union.
Wang G.,University of Houston |
Joyce J.,University of Puerto Rico at Mayaguez |
Phillips D.,UNAVCO |
Shrestha R.,University of Houston |
Carter W.,University of Houston
Landslides | Year: 2013
Light detection and ranging (LIDAR) is a remote sensing technique that uses light, often using pulses from a laser to measure the distance to a target. Both terrestrial- and airborne-based LIDAR techniques have been frequently used to map landslides. Airborne LIDAR has the advantage of identifying large scarps of landslides covered by tree canopies and is widely applied in identifying historical and current active landslides hidden in forested areas. However, because landslides naturally have relatively small vertical surface deformation in the foot area, it is practically difficult to identify the margins of landslide foot area with the limited spatial resolution (few decimeters) of airborne LIDAR. Alternatively, ground-based LIDAR can achieve resolution of several centimeters and also has the advantages of being portable, repeatable, and less costly. Thus, ground-based LIDAR can be used to identify small deformations in landslide foot areas by differencing repeated terrestrial laser scanning surveys. This study demonstrates a method of identifying the superficial boundaries as well as the bottom boundary (sliding plane) of an active landslide in National Rainforest Park, Puerto Rico, USA, using the combination of ground-based and airborne LIDAR data. The method of combining terrestrial and airborne LIDAR data can be used to study landslides in other regions. This study also indicates that intensity and density of laser point clouds are remarkably useful in identifying superficial boundaries of landslides. © 2013 Springer-Verlag Berlin Heidelberg.
Williams K.,UNAVCO |
Olsen M.J.,Oregon State University |
Roe G.V.,MPN Components |
Glennie C.,University of Houston
Remote Sensing | Year: 2013
A thorough review of available literature was conducted to inform of advancements in mobile LIDAR technology, techniques, and current and emerging applications in transportation. The literature review touches briefly on the basics of LIDAR technology followed by a more in depth description of current mobile LIDAR trends, including system components and software. An overview of existing quality control procedures used to verify the accuracy of the collected data is presented. A collection of case studies provides a clear description of the advantages of mobile LIDAR, including an increase in safety and efficiency. The final sections of the review identify current challenges the industry is facing, the guidelines that currently exist, and what else is needed to streamline the adoption of mobile LIDAR by transportation agencies. Unfortunately, many of these guidelines do not cover the specific challenges and concerns of mobile LIDAR use as many have been developed for airborne LIDAR acquisition and processing. From this review, there is a lot of discussion on "what" is being done in practice, but not a lot on "how" and "how well" it is being done. A willingness to share information going forward will be important for the successful use of mobile LIDAR. © 2013 by the authors; licensee MDPI, Basel, Switzerland.