Earth Science and Applications from Space National Imperatives for the Next Decade and Beyond (2007) / Chapter Skim
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8 Solid-Earth Hazards, Natural Resources, and Dynamics
8 Solid-Earth Hazards, Natural Resources, and Dynamics
Pages 217-256
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From page 217... ...
The continual change of the solid Earth on a wide range of timescales necessitates the use of global observations to develop the knowledge necessary for mitigation of natural hazards. For example, the earthquake cycle in seismically active regions typically has characteristic timescales of centuries to millennia.
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From page 218... ...
The second mission addresses how and why Earth's surface composition and thermal properties vary with location and time and has implications for resources, susceptibility to natural hazards, and ecosystem health. The third proposed mission seeks to determine much more accurately the topography of all seven continents; this would allow improved prediction of flood inundation and landslide likelihood and would provide an understanding of how topography evolves over time.
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From page 220... ...
2. Mission to observe surface composition and thermal properties.
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From page 221... ...
SOLID-EARTH HAZARDS, NATURAL RESOURCES, AND DYNAMICS 221 Propylitic Core Cuprite Hills Western Center West D U U D Prospect Faul t HWY 95 Eastern Center Desert Varnish + Goethite Jarosite Chlorite Other Fe-Minerals Goethite + Hematite Alluvial Fan Fe-Mineral(s) with Jarosite + Goethite + Jarosite _ Mineral Assemblage Broad 0.98 ∝m Band Fe-minerals + Trace Fe-Mineral(s)
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From page 222... ...
Although these three space-based missions are the primary recommendations and focus of this chapter, the panel also notes several other high priorities for solid-Earth science. These include the measurement and determination of the terrestrial reference frame and the use of suborbital technology for measurements that must be made either locally or at shorter distance and time intervals than is allowed by space observa
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From page 223... ...
Important observations of temporal and spatial variations in Earth's magnetic field will be provided by international missions. In summary, the challenges posed by resource discovery and production; by forecasting, assessment, and mitigation of natural hazards; and by advancing the science of solid-Earth dynamics call for ongoing investment in satellite capabilities.
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From page 224... ...
Post-facto remediation can be prohibitively expensive. Scientists, resource providers, policy makers and other stakeholders need an array of information to anticipate and mitigate natural hazards, ensure a steady supply of natural resources and energy, and develop appropriate international policies capable of sustaining life on Earth.
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From page 226... ...
. In 2000, annual losses from earthquakes were estimated at $4.4 billion per year for the United BOX 8.1 strateGic rOLes aNd QuestiONs fOr sOLid-earth scieNce aNd OBserVatiONs forecasting and Mitigating the effects of Natural hazards What observations can improve the reliability of hazard forecasts?
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From page 227... ...
Using three-dimensional dynamic stress modeling at reservoir scales, is it possible to more accurately model stress dynamics and in particular to predict failure processes on a basin scale? Terrains creating Can the risk of surface-water and groundwater pollution from mineral and hydrocarbon waste chemical risk sites be quantified from surface geochemical measurements?
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From page 228... ...
228 EARTH SCIENCE AND APPLICATIONS FROM SPACE FIGURE 8.5 Earthquakes produce substantial economic and human loss that could be mitigated with better warnings. In the Northridge, California, earthquake of January 17, 1994, buildings, cars and personal property were all destroyed when the earthquake struck.
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From page 229... ...
Such maps depict the probability of exceeding a specified magnitude of shaking over the next 30 to 100 years. The spatial resolution is typically on the order of tens to hundreds of kilometers.
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From page 230... ...
To improve hazard prediction for populated active volcanos, the size and shape of magmatic reservoirs must be determined from geodetic, seismic, gravity, and other geophysical observations. Researchers must also identify the type of magmatic unrest associated with eruptions, characterize detectable deformation prior to volcanic eruptions, and predict the volume and size of impending eruptive events.
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From page 231... ...
Currently, eruptions are monitored from orbit at coarse spatial resolution using MODIS on the EOS missions Terra and Aqua and at moderate resolution (90-m pixels) using ASTER on Terra (Patrick et al.,
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From page 232... ...
These motions reverse themselves for periods of 2-6 weeks every 14 or 15 months, as repeated slow earthquakes propagate across the area (see GPS measurements, right)
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. Improving the spatial resolution and swath width of an ASTER-like sensor would make it possible to detect changes earlier and could provide the foundation of a global eruption-prediction system.
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234 EARTH SCIENCE AND APPLICATIONS FROM SPACE 37° 54' 00" N 37° 53' 00" N 122° 17' 00" W 122° 15' 40" W FIGURE 8.7 InSAR image acquired over the Berkeley Hills, California, showing coherent down-slope motions that may be precursors of more rapid landslides. Increased down-slope movement in years with higher rainfall shows that potential hazard areas may be pinpointed in these high-resolution data and that hazard level may be assessed yearly.
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From page 235... ...
Indeed, the availability of high-resolution hyperspectral data will lead to comprehensive and precise surface geology characterization relevant for both resource exploitation and amelioration of environmental impact in the hydrocarbon- and mineral-extraction industry. Management of hydrocarbon resources is facilitated by measurements of surface deformation and surface composition (Box 8.4)
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From page 236... ...
Surface displacement Fault slip Fault slip Fault slip Reservoir compaction FIGURE 8.4.1 The schematic cross section illustrates how a gas reservoir with rapid variations in thickness could cause fault reactivation as a result of depletion. Pressures decline uniformly throughout the reservoir, but compaction varies by up to 20 percent because of abrupt changes in reservoir thickness across major faults.
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From page 237... ...
When combined with records on groundwater level and pumping, it also provides knowledge of hydrodynamic properties of the aquifer systems critical to measuring changes in the groundwater supply, modeling the aquifer system, and constraining the terrestrial water budget. Deformation measurements with national coverage and routine imaging would significantly advance the ability to characterize both regional- and continental-scale aquifer systems.
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From page 238... ...
238 EARTH SCIENCE AND APPLICATIONS FROM SPACE FIGURE 8.8 Cropland erosion processes driven by rain (top) and wind (bottom)
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From page 239... ...
. National coverage and routine imaging from space with high spatial resolution unachievable with a network of discrete surface stations would significantly advance understanding of the contributions of both human-induced and tectonic surface motions.
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From page 240... ...
240 EARTH SCIENCE AND APPLICATIONS FROM SPACE TABLE 8.2 Solid-Earth Panel Priorities and Associated Mission Concepts Related Synergies Planned or Summary of Type of Spatial with Other Integrated Mission Focus Variables Sensor(s) Coverage Resolution Frequency Panels Missions Surface Strain InSAR Global 50-75 m ~weekly Climate DESDynI deformation accumulation Ecosystems in seismogenic Water zones; volcano monitoring; stress changes and earthquake triggering; hydrocarbon reservoir monitoring; landslides; solid-Earth dynamics Surface Volcano Hyperspectral Global; 50-75 m 30 day, Ecosystems HyspIRI composition monitoring; visible and near pointable pointable to Water and thermal hydrocarbon, IR, thermal IR daily properties mineral exploration; assessment of soil resources; landslides; solid-Earth dynamics High- Landslides; Imaging lidar Global 5m Monthly to Ecosystems LIST resolution floods; solid- occasional Water topography Earth dynamics Temporal Groundwater Microwave or Global ~Monthly Climate GRACE-II variations storage; glacier laser ranging Water in Earth's mass balance; gravity field ocean mass distribution; signals from post-glacial rebound, great earthquakes Oceanic Seafloor Altimeter Global ~6 km Climate SWOT bathymetry topography Ecosystems Health Water
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From page 241... ...
measuring and monitoring variations in Earth's gravity field via a GRACE follow-on and gradiometry; and (6) measuring and monitoring variations in Earth's magnetic field via satellite, balloon, and UAV observations.
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From page 242... ...
along-track interferometry for ocean surfaces and other fast-moving objects. The InSAR mission recommended by the panel would be a major technological advance over existing systems (Table 8.3)
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From page 243... ...
Coverage of any specific area from an exactly repeated orbit will be provided every 24 days. earth surface deformation Mission contributions New science: Global, fine-resolution map of strain accumulation, subsidence from water and hydrocarbon extraction, and characterization of earthquake, volcano, and landslide natural hazards Applications: Earthquake risk assessment, volcanic hazard prediction, monitoring of changes in groundwater and hydrocarbon reserves Mission to Observe surface composition and thermal properties Mission summary -- surface composition and thermal properties Variables: Volcano monitoring; hydrocarbon exploration; mineral exploration; assessment of soil resources; landslides; solid Earth dynamics Sensors: Hyperspectral visible and near IR, thermal IR Orbit/coverage: LEO/global access Panel synergies: Ecosystems, Water Many solid-Earth problems that can be addressed by remote sensing from Earth orbit are in the category of environmental geology.
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From page 244... ...
surface composition and thermal properties Mission contributions New science: Surface composition from maps of fine-resolution hyperspectral observations in optical and near-infrared, thermal emissivity and thermal inertia, mapping of gas release from processes at depth Applications: Volcanic hazards, resource exploitation and extraction, ecological drivers
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From page 245... ...
However, these same features are clearly visible at 5-m resolution, making it possible not only to map natural hazards, but also to detect changes in surface topography through time, and to better understand the processes that shape Earth's surface. Lidar systems permit very precise (<10 cm height error)
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From page 246... ...
The panel recommends pursuing the lidar mission because of its greater accuracy and complementary use for improving measurements of ecosystem structure, but data from TanDEM-X would allow important progress to be made before the lidar mission is flown later in the decade. high-resolution topography Mission contributions New science: High-resolution, high-precision topographic data, in most cases with vegetation effects quantified and removed Applications: Geomorphology, landslide hazards, flooding, hydrology, ecology Mission to Monitor temporal Variations in earth's Gravity field Mission summary -- temporal Variations in earth's Gravity field Variables: Ground water storage; glacier mass balance; ocean mass distribution; signals from post-glacial rebound, great earthquakes Sensors: Microwave or laser ranging Orbit/coverage: LEO/global Panel synergies: Climate, Water The problem of temporal variations in Earth's gravity field is inherently interdisciplinary.
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From page 247... ...
temporal Variations in earth's Gravity field Mission contributions New science: Separation of time-varying gravity signal from postglacial rebound from changes caused by ongoing redistribution of water and ice mass; monitoring of postseismic relaxation Applications: Geodynamic studies, improved estimates of tide gauge motions Mission to Measure Oceanic Bathymetry Mission summary -- Oceanic Bathymetry Variables: Seafloor topography Sensors: Altimeter (nadir or swath) Orbit/coverage: LEO/global Panel synergies: Climate, Ecosystems, Health, Weather Variations in the pull of gravity caused by seafloor topography cause slight tilts in ocean surface height, measurable by satellite altimeters.
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From page 248... ...
Ocean Bathymetry Mission contributions New science: Geologic processes responsible for ocean floor features, distribution of seafloor roughness Applications: Tsunami hazard forecasts, ocean circulation, navigation Monitoring the Geomagnetic field Understanding the origin of Earth's magnetic field was ranked by Albert Einstein as among the three most important unsolved problems in physics. Although it is now known that the magnetic field is generated in the convecting metallic outer core, where self-generating dynamo action maintains the field against decay, the detailed physics by which the dynamo operates is not well understood.
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From page 249... ...
Rapid deformation before or after earthquakes or during volcanic eruptions could be analyzed suborbitally on time scales not easily sampled with spacecraft. The use of stratospheric platforms for in situ and remote Earth science measurements warrants revolutionary concepts.
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From page 250... ...
Magnetic field Observations Observations of spatial and temporal variations in Earth's magnetic field will be dominated in the next decade by international missions such as SWARM. It is crucial for NASA to facilitate participation and access to the data for U.S.
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From page 251... ...
synergistic Observations from Other panels Spatially dense crustal-deformation measurements are the primary data need recognized by the solidEarth panel. Acquisition of the data is also a high priority of the climate and ecosystem panels, specifically for the observation of ice flow in the polar ice sheets and characterization of vegetation canopy structure and biomass.
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From page 252... ...
The panel has identified three space missions as crucial: an InSAR mission to accomplish global characterization of the deformation of Earth's crust, a hyperspectral optical and near-infrared mission to observe and record surface composition and thermal properties, a mission to measure land-surface topography precisely. Missions to determine long-term variations in Earth's gravity field, to determine ocean bathymetry with improved spatial resolution, and to observe the spatial and temporal variations in the geomagnetic field are also important.
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From page 253... ...
1991. Solid Earth Science in the 1990s, Volume 1 -- Program Plan, NASA Technical Memorandum 4256, Washington, D.C., 61 pp.
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From page 254... ...
99:15423-15438. SESWG (Solid Earth Science Working Group)
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From page 255... ...
science community to address its science objectives, and in any case does not see how there will be sufficient participation by U.S. scientists to define the proper orbits and coverage to begin to meet U.S.
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From page 256... ...
But it still cannot do repeat-pass interferometry, the cornerstone of all the planned major science objectives. In summary, the panel notes that the U.S.
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