United States of America

Filter Total Items: 2,990
Date published: May 15, 2021
Status: Active

Alaska North Slope LiDAR

High-resolution light detection and ranging (lidar) elevation data were acquired along the north coast of Alaska between 2009 and 2012. The lidar acquisition, from Icy Cape, Alaska to the United States/Canadian border, comprised approximately 11,000 km2. The airborne lidar data were acquired in support of the U.S. Geological Survey...

Date published: October 18, 2019
Status: Active

Filtering of Elevation Difference Mask to Identify True Topographic Changes

The output of the differencing and thresholding procedures described above was a set of pixels with elevation differences large enough to be judged significant. Ideally, these differences would represent the set of true topographic changes that could then be used for further analysis. In reality, this was not the case, as the selected differences included areas that clearly did not reflect...

Contacts: Dean Gesch
Date published: October 18, 2019
Status: Active

Significant Change Thresholds

The next step in the data processing procedure was to threshold the difference grids to isolate areas of significant change. This procedure is commonly done in the image differencing method of change detection, and the threshold is often based on the standard deviation value of the differences. As implemented for this study, the thresholding approach incorporated the inherent absolute vertical...

Contacts: Dean Gesch
Date published: October 17, 2019
Status: Completed

What if the ShakeAlert Earthquake Early Warning System Had Been Operating During the M6.9 1989 Loma Prieta Earthquake?

How will ShakeAlert® likely perform now on a large earthquake impacting a major urban area? How much warning will you get? To answer this, let’s do a thought experiment...

Date published: October 17, 2019
Status: Active

Ecosystems: EXPRESS

The continental shelf and slope offshore California, Oregon, and Washington are home to deep-sea corals, chemosynthetic communities, and other sensitive habitats that could be impacted by the development of energy and mineral resources. The EXPRESS campaign will map and...

Date published: October 17, 2019
Status: Active

Resources: EXPRESS

Along the U.S. west coast, the Pacific Ocean, ocean floor, and winds above contain potentially vast energy and mineral resources. Developing these resources safely and wisely requires detailed information for each area of interest. One goal of EXPRESS is to inform ocean...

Date published: October 17, 2019
Status: Active

Hazards: EXPRESS

Marine geohazards including earthquakes, landslides, and tsunamis lie offshore of densely populated areas of California, Oregon, and Washington. One goal of EXPRESS is to improve assessments of these hazards.

Date published: October 16, 2019
Status: Completed

Earth As Art 6

As always, our newest collection of Earth As Art relies on the interplay of visible and invisible light across the electromagnetic spectrum made possible by satellite sensors. The stunning views seen in Earth As Art 6 carry on that two decade tradition, but also include high-resolution imagery captured by Unmanned Aircraft Systems - commonly referred to as drones - for the first time.  ...

Contacts: Janice Nelson
Date published: October 16, 2019
Status: Active

Beavers Impacting Tundra Ecosystems (BITE)

The range expansion of the North American beaver (Castor canadensis) has implications for water quality, aquatic ecosystems, and fisheries in Arctic streams.

Contacts: Michael P Carey, Ph.D., Joshua C Koch, Ph.D., Brett A Poulin, PhD, Jonathan O’Donnell, PhD, Ken Tape, PhD
Date published: October 16, 2019
Status: Active

California Seafloor Mapping Program

The California Seafloor Mapping Program (CSMP) is a cooperative program to create a comprehensive coastal/marine geologic and habitat base map series for all of California's State waters. The California Ocean Protection Council (COPC) authorized funds to establish the CSMP in 2007 (...

Date published: October 14, 2019
Status: Completed

Accuracy Assessment of Elevation Data

The thresholding approach (described below) used to distinguish significant differences from the raw difference grids requires a measure of the absolute vertical accuracy of each input elevation dataset. The NED and SRTM data were compared to an independent reference geodetic control point dataset from NGS. These points have centimeter-...

Contacts: Dean Gesch
Date published: October 14, 2019
Status: Active

Southern California / Channel Islands - Topobathymetric Elevation Model of the Channel Islands

Located in the Pacific Ocean off the coast of California, the Channel Islands are a chain of eight islands where years of isolation has created unique fauna, flora, and archeological resources. Five of the islands are part of Channel Islands National Park (Anacapa, Santa Cruz, Santa Rosa, San Miguel, and Santa Barbara), and the waters surrounding these islands make up the Channel Islands...