The Earth’s surface plays a critical role in the Earth system by interacting with the ocean and the atmosphere. To understand the Earth system, scientists must observe how the Earth’s surface changes as a result of interactions between the atmosphere and ocean (coastal erosion, landslides) and how tectonics and volcanism impact the atmosphere and ocean. Monitoring the Earth’s surface and interior also helps societies understand and respond to natural hazards.
The six scientific challenges under this science focus area are:
- What is the nature of deformation at plate boundaries and what are the implications for earthquake hazards?
- How do tectonics and climate interact to shape the Earth’s surface and create natural hazards?
- What are the interactions among ice masses, oceans, and the solid Earth and their implications for sea level change?
- How do magmatic systems evolve and under what conditions do volcanoes erupt?
- What are the dynamics of the mantle and crust and how does the Earth’s surface respond?
- What are the dynamics of the Earth’s magnetic field and its interactions with the Earth system?
Terra and Earth Surface and Interior
Terra has more than a decade of observations showing how earthquakes, volcanic eruptions, floods, landslides, and coastal erosion have altered Earth’s surface. The measurements also show how Earth’s surface is changing as a result of both short-term climate variability (drought) and climate change (melting ice sheets and glaciers).
Routine Disaster Monitoring
Terra instruments provide a bird’s-eye view of natural disasters as they occur. Such a view may often be the only way to gauge the full scope of the event, and as such, is extremely valuable to responders. Two Terra instruments are routinely used to monitor hazards: MODIS and ASTER.
MODIS has a near-global view every day and thus can provide imagery of an event nearly every day. The LANCE Rapid Response System provides MODIS images in near-real time in a format compatible with mapping programs. Users include the U.S. Forest Service, UN World Food Programme, the Environmental Protection Agency, and other international organizations.
ASTER was specifically designed and built to observe local- and regional-processes that occur near or on Earth surface at 15 meters per pixel. One of the ASTER telescopes is movable, so that it can be rapidly directed to image the disaster region.
MODIS daily images are used to track volcanic ash, which can damage jet engines. MISR has also been used to estimate volcanic plume height to provide a better estimate of where ash is in the atmosphere. Both MODIS and MISR measurements help decision makers divert air traffic away from ash plumes.
MODIS and ASTER also work together to monitor volcanic activity, particularly in remote regions. When MODIS detects a thermal anomaly over a volcano, an automatic scheduling program triggers a request for a high-resolution ASTER image of the volcano. ASTER’s high resolution visible, infrared, and thermal infrared measurements provide unprecedented information about erupting volcanoes.
Listen to ASTER scientist Dave Pieri talk about keeping planes safe by watching volcanoes from space on these podcasts (external site) available from EarthSky.
Listen to Michael Ramsey discuss monitoring volcanoes from space in this EarthSky podcast (external link).
Terra responds to floods by providing images from ASTER, MODIS, and MISR. The images are used to map flood extent and impact. MODIS images support an automated flood mapping system.
Earthquakes and Landslides
ASTER images can be used to identify landslides in the wake of earthquakes or severe storms.