Prediction of the impacts of potential earthquakes is enhanced by detailed and accurate data on fault structures. From 2013–2014, the USGS and Utah State partners acquired 3,682 km2 of 8 points/m (Quality Level 1) lidar for areas along the Wasatch Front in Utah. The data span the urbanized areas of Salt Lake and Utah Counties, and the entire length of the Wasatch Fault from Sanpete County north into Oneida County in southeastern Idaho.
Hazards - Earthquakes
Earthquake Early Warning (EEW) systems use earthquake science and monitoring technology to alert people when shaking waves generated by an earthquake are expected to arrive at their location. The seconds to minutes of advance warning can allow people to take actions to protect life and property. Research shows, however, the alerts generated by EEW can be improved by incorporating data from the Global Navigation Satellite System (GNSS).
The hazard posed by earthquakes is strongly related to the geologic slip rate of active faults. To determine slip rates, geologists use high-resolution digital elevation maps (DEMs) to reconstruct landforms offset by meters to hundreds of meters by active faults. Scientists at the Earthquake Science Center in Pasadena, California, are working to improve methods for obtaining low-cost but high-resolution DEMs using structure from motion (SfM) photogrammetry. SfM software utilizes a set of overlapping photographs to determine the relative camera position and orientation of each photo viewp
In 2001, a nearly 5-month-long sequence of shallow, mostly small magnitude earthquakes occurred beneath Spokane, Washington (population 200,000). During most of the sequence, the locations of the earthquakes were not well determined because seismic instrumentation was sparse. The earthquake hypocenters were likely very shallow, because residents near the city center both heard and felt many of the earthquakes.
The Balochistan, Pakistan, earthquake (magnitude 7.7) ruptured an approximately 200-km-long stretch of the Hoshab Fault in southern Pakistan on September 24, 2013. To help understand the impact of such a large event, scientists at the the USGS Geologic Hazard Science Center (Golden, Colorado) mapped the resulting ground surface rupture using high-resolution (0.5 m) pre- and post-event satellite imagery accessed via Digital Globe’s Enhanced View WebHosting platform.
The New Madrid seismic zone (NMSZ) in southeastern Missouri and northeastern Arkansas has been responsible for producing some of the largest intraplate earthquakes on record. The USGS Earthquake Hazards Program provided funding for a collaborative effort to acquire several thousand square kilometers of airborne lidar data and derivative bare-earth ground models to support earthquake hazard studies in the NMSZ.
Hazards - Other
The Alaska Volcano Observatory utilizes satellite remote sensing to help monitor the 52 historically active volcanoes that comprise the 2,500-km-long Aleutian Arc. The primary volcanic hazard is to aviation along the busy North Pacific air routes. Remote sensing provides information that is used to detect, characterize, and monitor volcanic activity, particularly ash plumes, which can damage and clog jet engines.
After a major disaster, a satellite image or a collection of aerial photography is frequently the fastest, most effective way to determine the scope and severity of the event.
In 1999, an international consortium of space agencies formed the International Charter ‘Space and Major Disasters’ as a mechanism to provide satellite data to evaluate disaster impacts in support of disaster relief worldwide. Since the Charter’s formation in 1999, its membership has grown to 15 space organizations managing more than 20 Earth-observing satellites. The data from these satellites have helped emergency managers worldwide to deal with a variety of natural and man-made disasters.
The USGS is investigating how lidar can be used to assess wildfire risk in the wildland urban interface. Lidar data, building composition, and landscape characteristics were used to quantify the prefire conditions that increase or decrease the likelihood of structure ignition and consumption in a destructive wildfire event. The Black Forest Fire of 2013 near Colorado Springs, Colorado, will be used to illustrate how prefire aerial lidar data can characterize vegetation and fuels within the home ignition zone and determine structure locations under a closed forest canopy.