How can sudden events affect earth

More answers. Q: How can sudden events affect Earth? Write your answer Related questions. How can sudden events effect earth? What are the events that cause the Earth to quake and shake?

What information can you learn about the earth when studying catastrophic events? Can oxygen catastrophic events in the Earth's history that can be tracked through sudden changes? How do catastrophic events affect the earth's surface? How can events on the Sun affect the Earth? How does sudden shifts in the Earth's crust affect the ocean?

How do sudden geological changes or extreme weather conditions affect the Earth's surface? How are people affected by events and forces inside the earth? How do the plate movements affect geological events on the earth's surface? How can sudden events effect the earth? What natural events affect climate? What is earthshaking events? Uniformitarianism and catastrophism? What do you call the sudden movement of the Earth's crust?

A sudden movement in the Earth's crust? What is sudden storm? Will color preference affect sudden choices?

What is a sudden movement in the Earth's crust? What is the sudden shaking of the earth called? What is the sudden stress changes in the earth that cause ground shaking? What is the sudden stress changes in the earth that cause ground shaking.? How did the fall of mankind and the flood affect the earth?

People also asked. Fossil evidence from this time period confirms that Antarctica was connected to Australia and South America and much warmer than it is today. Most volcanoes occur at plate boundaries, where two plates are moving away diverging or together converging.

Volcanic eruptions may be explosive violent or effusive passive , depending on the lava chemistry amounts of silica and dissolved gases. Silica is a mineral found in nature as sand or quartz.

High levels of silica mean very viscous thick lava, and low levels mean more fluid lava. Dissolved gases build up inside the volcano, much like a can of soda or other carbonated beverage. The higher the level of gas, the more pressure that builds — and the more violent an explosion. The combination of silica and dissolved gas levels determines the type of eruption and shape of the volcano.

Largely unexplored, the Gakkel Ridge runs underneath the Arctic Ocean. Scientists have discovered volcanic craters and evidence of surprisingly violent eruptions in the recent past. Map courtesy of the National Oceanic and Atmospheric Administration. Antarctica, too, is home to volcanic activity. Ross Island, located in the Ross Sea, is composed of three extinct volcanoes Mt. Bird, Mt.

Terror, and Hut Point and Mt. The summit of Mt. Erebus from the front seat of a helicopter. Photo courtesy of Mt. Erebus Volcano Observatory.

Erebus is home to a permanent lava lake, or a large amount of molten lava contained in a crater. Only three volcanoes in the world have permanent lava lakes, making Mt. Erebus an important research site for scientists looking to better understand the internal plumbing system of volcanoes.

However, its location permits only a six-week field season and its high altitude meters is physically challenging. Erebus lava lake in Erebus is also notable for its persistent low-level eruptive activity with almost daily eruptions. While the volcano has had some history of violent activity, most eruptions are passive lava flows similar to the volcanoes of Hawaii. Seismic activity earthquakes is most often associated with tectonic plate boundaries. As plates slowly move, their jagged edges stick and suddenly slip, causing an earthquake.

The Gakkel Ridge underneath the Arctic Ocean experiences small earthquakes that accompany the volcanic activity found in the area. Antarctica, which lies in the center of a tectonic plate, does not experience many earthquakes. However, seismic activity is associated with eruptions of Mt.

Use these resources to learn more about erosion, volcanoes, earthquakes, and plate tectonics and how these agents of change affect the polar regions. All About Glaciers Learn how glaciers form, move, and shape the landscape. Katabatic Winds Basic information about the winds of Antarctica. National Geographic: Forces of Nature Explore volcanoes and earthquakes in this web site.

Polar Discovery: Arctic Seafloor Expedition During summer , a team of scientists used autonomous underwater vehicles to explore the Gakkel Ridge. The Polar Discovery web site documents the expedition and provides background information, images, and video.

Erebus Volcano Observatory Provides general information about Mt. Erebus, ongoing research, video, and a photo gallery. The entire National Science Education Standards document can be read online or downloaded for free from the National Academies Press web site.

The following excerpt was taken from Chapter 6. Blewitt, and E. A geodetic plate motion and global strain rate model. Geochemistry, Geophysics, Geosystems 15 10 Kump, L. Brantley, and M. Chemical weathering, atmospheric CO 2 , and climate. Annual Review of Earth and Planetary Sciences Lamb, M. Scheingross, W.

Amidon, E. Swanson, and A. A model for fire-induced sediment yield by dry ravel in steep landscapes. Journal of Geophysical Research F Lange, H. Casassa, E. Ivins, L.

Fritsche, A. Richter, A. Groh, and R. Observed crustal uplift near the Southern Patagonian Icefield constrains improved viscoelastic Earth models. Geophysical Research Letters Lay, T. Aster, D. Forsyth, B. Romanowicz, R. Allen, V. Cormier, and J. Report to the National Science Foundation. Leuliette, E. Contributions of Greenland and Antarctica to global and regional sea level change. Oceanography 29 4 Lipman, P.

Mullineaux, eds. The Eruptions of Mount St. Helens, Washington No. Reston, VA: U. Department of the Interior, U. Geological Survey. Milne, G. Searching for eustasy in deglacial sea-level histories. Quaternary Science Reviews 27 Molnar, P.

Late Cenozoic uplift of mountain ranges and global climate change: Chicken or egg? Nerem, R. Beckley, J. Fasullo, B. Hamlington, D. Masters, and G. Climate-change-driven accelerated sea-level rise detected in the altimeter era. Proceedings of the National Academy of Sciences 9 New Research Opportunities in the Earth Sciences.

Pail, R. Bingham, C. Braitenberg, H. Dobslaw, A. Eicker, A. Horwath, E. Longuevergne, I. Panet, and B. Science and user needs for observing global mass transport to understand global change and to benefit society.

Surveys in Geophysics 36 6 Peltier, W. Global glacial ice volume and Last Glacial Maximum duration from an extended Barbados sea level record. Quaternary Science Reviews Porder, S. Asner, and P. Ground-based and remotely sensed nutrient availability across a tropical landscape.

Proceedings of the National Academy of Sciences 31 Prata, A. Geophysical Research Letters 34 5 :L Pritchard, H.

Arthern, D. Vaughan, and L. Extensive dynamic thinning on the margins of the Greenland and Antarctic ice sheets. Pritchard, M. Geochemistry, Geophysics, Geosystems 5 2. Reath, K. Ramsey, J. Dehn, and P. Predicting eruptions from precursory activity using remote sensing data hybridization. Journal of Volcanology and Geothermal Research Savage, J. Interseismic deformation at the Nankai Trough, Japan, subduction zone. Smith, B. Fricker, I. Joughin, and S.

Journal of Glaciology 55 Stanley, T. A heuristic approach to global landslide susceptibility mapping. Natural Hazards 87 1 Syvitski, J. Kettner, I. Overeem, E. Hutton, M. Hannon, G. Brakenridge, J. Day, C. Saito, L. Giosan, and R. Sinking deltas due to human activities.

Voigt, S. Giulio-Tonolo, J. Lyons, J. Jones, T. Schneiderhan, G. Platzeck, et al. Global trends in satellite-based emergency mapping. Willett, S. Orogeny and orography: The effects of erosion on the structure of mountain belts.

McCoy, J. Perron, L. Goren, and C. Dynamic reorganization of river basins. Zoback, M. Geist, J. Pallister, D. Hill, S. Young, and W. Advances in natural hazard science and assessment, Geological Society of America Special Paper We live on a dynamic Earth shaped by both natural processes and the impacts of humans on their environment. It is in our collective interest to observe and understand our planet, and to predict future behavior to the extent possible, in order to effectively manage resources, successfully respond to threats from natural and human-induced environmental change, and capitalize on the opportunities — social, economic, security, and more — that such knowledge can bring.

By continuously monitoring and exploring Earth, developing a deep understanding of its evolving behavior, and characterizing the processes that shape and reshape the environment in which we live, we not only advance knowledge and basic discovery about our planet, but we further develop the foundation upon which benefits to society are built. Thriving on Our Changing Planet presents prioritized science, applications, and observations, along with related strategic and programmatic guidance, to support the U.

Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website. Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book. Switch between the Original Pages , where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text. To search the entire text of this book, type in your search term here and press Enter.

Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available. Do you enjoy reading reports from the Academies online for free? Sign up for email notifications and we'll let you know about new publications in your areas of interest when they're released. Get This Book. Visit NAP. Looking for other ways to read this? No thanks. Page Share Cite. MI S-1a. MI S-1b. Measure and forecast interseismic, preseismic, coseismic, and postseismic activity over tectonically active areas on time scales ranging from hours to decades.

VI S-1c. Forecast and monitor landslides, especially those near population centers. One objective ranked Important S-1d. S-2 How do geological disasters directly impact the Earth system and society following an event? MI S-2a. Rapidly capture the transient processes following disasters for improved predictive modeling, as well as response and mitigation through optimal retasking and analysis of space data.

VI S-2b. VI S-2c. Assess co- and postseismic ground deformation spatial resolution of m and an accuracy of 10 mm and damage to infrastructure following an earthquake. S-3 How will local sea level change along coastlines around the world in the next decade to century? MI S-3a. MI S-3b. S-4 What processes and interactions determine the rates of landscape change?

MI S-4a. Two objectives ranked Important S-4b and S-4c. VI S-5a. Two objectives ranked Important S-5b and S-5c. S-6 How much water is traveling deep underground and how does it affect geological processes and water supplies? VI S-6a. Determine the fluid pressures, storage, and flow in confined aquifers at spatial resolution of m and pressure of 1 kPa 0. Three objectives ranked Important S-6b, S-6c, and S-6d. S-7 How do we improve discovery and management of energy, mineral, and soil resources?

One objective ranked Important S-7a. Implementing the vision outlined earlier will enable advances in the following scientific and applications areas: Forecasting natural disasters, including the timing and size of earthquakes, the timing and duration of volcanic eruptions, and the timing and location of landslides.

Responding rapidly to natural disasters and mitigating their consequences. Quantifying global, decadal landscape change owing to surface processes, tectonics, and societal activities. Understanding and forecasting regional variations in sea-level rise. Measuring and forecasting vertical land motion along coastlines to assess and mitigate hazards from relative sea-level rise.

Quantifying mantle convection to understand how it drives plate motions and generates earthquakes and volcanic eruptions. Understanding temporal variations of water discharge and subsurface water storage and transport. Understanding Earth surface and interior processes caused or influenced by anthropogenic activity. Benefits of Prior Investments in Earth Observing Satellites Over the past two decades, advances in observational capabilities—including Synthetic Aperture Radar SAR interferometry, time-variable gravity, global and bare-earth topography, laser and radar altimetry, magnetometry, and hyperspectral imaging—have underpinned new scientific insights.

Detection and Compositional Analysis of Volcanic Plumes Greatly improved temporal and spatial resolution in multi- to hyperspectral data has driven remarkable new insights on volcanic systems and the plumes they produce. Repeated SAR acquisitions provide maps of ground displacement used to understand locations of possible large aftershocks and postseismic activity.

This interferogram shows the benefits of using the longer wavelength SAR technology to be deployed in the NISAR mission for mapping line-of-sight ground displacement in a region of extreme topography. Water loading in the Himalayan foreland owing to the annual summer monsoon is interpreted to flex the crust downward, causing extensional stresses that oppose the tectonically driven north-south contraction.

These reduced rates of contraction are interpreted to cause decreasing rates of earthquakes and can be observed only using satellite-based measurements. A: SO 2 plume from the active lava flow. B: Much larger degassed SO 2 plume from the vent, following the collapse of the crater, indicating an extensive, previously unrecognized active hydrothermal system.

Sea Level and Global Redistribution of Water and Mass One of the most important discoveries over the past two decades is that sea-level rise is highly variable around Earth, with some regions e.

The global mean change over this period was 7 cm. The larger regional patterns are the result of decadal changes in the winds, ocean circulation, and heat and mass redistribution. The isolated lake provides a clue to a topography disrupted by landslides.

Right panel: Lidar bare-earth, shaded relief topography exposes multiple generations of landslides with diverse modes of failure and movement, including mass flows, block rotations, and gravitational collapse. Back rotation in the headward area of the large slide ponded drainages and created the upland lake. Inset shows the decadal gravimetric changes owing to the Tohoku earthquake. Science Questions and Objectives Question S How can large-scale geological hazards be accurately forecast in a societally relevant time frame?

Priority—Most Important: Volcanic eruptions are likely to pose an increasing threat as more people move to coasts along subduction zones, where most volcanoes occur. A combination of ground-based and space-based observations are needed to monitor volcanoes and forecast eruptions.

Space-based observations provide a means to collect data on all volcanoes, and may be the only practical avenue for collecting data in remote or dangerous areas. Systematic monitoring has led to accurate forecasts of the timing and duration of some eruptions. Relevant quantities: Three quantities need to be measured and monitored.

The first is the changing shape of the volcano measured using InSAR. Expansion or contraction of the summit region provides an estimate of the changing magma supply volume and depth beneath the volcano, and larger FIGURE Helens on May 18, The eruption was the most disastrous in U.

The second quantity is the composition and quantity of the gas emitted prior to and during an eruption as well as the composition of any ash, which provide insight into the drivers and intensity of eruptions. Thermal measurements are made using multi- to hyperspectral data spanning the visible to shortwave infrared VSWIR and TIR region, depending on the temperature of the surface, but high-quality TIR data are critical for detecting the small-scale temperature changes of the surface leading up to an eruption Figure Length and time scales over which responses should be quantified: Changes in SO 2 , CO 2 , and other gas emission rates e.

Variations in these parameters occur at a much higher frequency as the eruption proceeds, and require much improved temporal observations e. Detectable changes in volcano shape, gas emissions, and thermal output prior to a new eruption event occur over time scales ranging from months to minutes. The relevant length scales are 10 m to km for surface and plume measurements, with most shape changes occurring over length scales greater than 1 km. The necessary vertical precision mm and the temporal frequency need to be adjusted to match the activity of a particular volcano.

Priority—Most Important: GPS measurements of surface deformation reveal that earthquake cycles contain much richer behavior than previously thought. For example, the Cascadia subduction zone fault is accumulating elastic energy that will eventually be released in a catastrophic earthquake offshore Washington and Oregon Figure Over the past decade space-based measurements have revealed that this steady strain accumulation is punctuated by creep events that occur at the down-dip limit of the locked fault.

Similar transient slip behavior has been observed at most megathrust earthquake zones globally, as well as around the locked zones of the San Andreas fault system. Measuring the details of these transients over time scales of days and years may provide insight into the physics of the earthquake cycle and ultimately support forecasts of the timing of a major rupture on socially relevant time scales.

Relevant quantities: Four main types of measurements are needed. The first is related to the interseismic crustal deformation surrounding a locked fault. The length of time since the last rupture multiplied by the rate of interseismic crustal deformation can be used to assess the magnitude and probability of the occurrence of earthquakes.

Terrestrial measurements from seismometers and GPS will provide the high temporal sampling needed to observe co- and postseismic deformation and ground shaking.

Space-based InSAR and high-resolution optical imagery will provide the high spatial resolution needed to observe the near-fault co- and postseismic deformation. For very large earthquakes, temporal variations in gravity can reveal large-scale offshore deformation not observable by other methods.

Last, high-resolution bare-earth topography along areas of surface rupture can be used with surface dating methods to decipher the rupture history of a fault over many earthquake cycles. Length and time scales over which responses should be quantified: Surface deformation associated with the earthquake cycle occurs over spatial scales ranging from meters to thousands of kilometers and time scales ranging from seconds to thousands of years.

The relevant deformation scales observable from spaceborne radar interferometry range from 10 m to km. Particularly critical are measurements of slow slip events e.

Co- and postseismic processes require frequent acquisitions 12 days or shorter over seismically active areas. High-resolution bare-earth topography needs to be measured only once before an event at 5 m spatial resolution and 1 m vertical accuracy for topographic correction of interferograms as well as for paleoseismic studies.

Priority—Very Important: Landslides typically affect fewer people than large-scale volcanic eruptions and earthquakes, yet they regularly cost lives and disrupt economies.

Sudden landslides can be triggered by heavy precipitation, earthquakes, or volcanic eruptions. Steep slopes are the most important factor in making an area susceptible to landslides, but other key factors include recent rainfall or wildfire, seismicity and the presence of nearby faults, the strength of bedrock and soils, deforestation, and the presence of roads. Landslide susceptibility has been mapped using space-based data Figure The last rupture in caused 2 m of subsidence along the Washington shoreline and generated a large tsunami that impacted the entire Pacific Basin.

Lower panel: GPS and seismicity measurements at station ALBH over the past 18 years shows the gradual accumulation of stress on the fault that is punctuated with slow slip events at month intervals.

This episodic tremor and slip occurs at the expected nucleation site of a major earthquake, and so understanding the phenomena will aid in earthquake forecasting. Dragert, Geological Survey of Canada, March Measurement estimates.

An important objective is to detect and monitor slow-moving landslides and to shorten forecasts of sudden collapse events e. Length and time scales over which responses should be quantified: The relevant length scales range from meters to tens of km, and time scales range from seconds to years. High-resolution, bare-earth topography at m spatial resolution and 0. Subsequently, more frequently acquired data are required prior to a suspected slide event and then following its occurrence. High spatial resolution images from commercial sources are ideal for linking topography to land cover and eventually for mapping composition from space.

Priority—Important: Tsunamis are one of the most destructive hazards on Earth, yet satellites are only peripheral in monitoring their generation and propagation. Mapping ionospheric waves has recently provided some limited information on tsunami propagation.

Improved models of the shape of the seafloor as well as high-resolution coastal topography are critically needed to improve modeling of tsunami run-up and its impact on coastal populations. Relevant quantities: Key measurements are in situ seismicity, ground deformation via GPS, and seafloor pressure changes. The most important contribution from a space or aircraft mission is high-resolution 1 m spatial and 0.

New swath altimetry technology, such as the planned SWOT mission, could dramatically increase the accuracy and resolution of the global bathymetry. Length and time scales over which responses should be quantified: The bathymetry and topography only need to be measured once, followed by repeat measurements after a significant change. Linkages of S-1 Objectives to Other Panels and Integrating Themes Extreme events like volcanic eruptions, earthquakes, tsunamis, and large landslides can have spatially extensive consequences on hydrology, ecology, weather, climate, and human habitability.

Priority—Most Important: Rapid capture and delivery of synoptic data by spaceborne assets following a disaster can directly mitigate the loss of life and infrastructure. These data can be obtained by rapidly retasking existing satellites, deploying new satellites dedicated to a specific measurement objective, or by deploying a constellation of future satellites that provide the temporal fidelity required.

An example of the international response to the earthquakes and landslides in Nepal is shown in Figure Relevant quantities: The relevant quantities are largely defined by the disaster and available space assets. Repeated InSAR and high-resolution optical data can provide information on both the magnitude of the ground motion and the decorrelated regions where a majority of the infrastructure may be damaged.

Hyperspectral UV through TIR data are especially valuable for monitoring ongoing changes in the temperature, composition, and extent of erupted volcanic materials, including gases, as well as constraining forecasts of the duration of the activity.

High-resolution topography enables quantified assessments of landscape change owing to erosion, deposition, and vegetation disturbance. An important objective for all of these data is the rapid dissemination of higher level products to local emergency responders and the global scientific community.

Length and time scales over which responses should be quantified: The scales are dictated by the extent and duration of the disaster. In the case of the Nepal earthquakes see Figure However, the threats from additional large aftershocks may persist for months to years following an event.

Volcanic eruptions and their secondary hazards e. Priority—Very Important: Active volcanoes can erupt intermittently or continuously for decades or more. Consequently, ongoing data collection is required to determine whether the eruption is waning, increasing, or transitioning to a new phase. These synoptic data of the estimated 1, Disaster categories are 1 hydrometeorological, including flood, storm, snow, wildfire, and drought events blue symbols ; 2 geophysical, including earthquake, volcano, and landslide events red symbols ; and 3 biogenic, including epidemic outbreaks and technical accidents green symbols.

Polygons highlight clustering of activations for the various disaster categories. All three panels show population density in the background. The earthquake destroyed centuries-old buildings, killed nearly 9, people, and left hundreds of thousands homeless.

The shaking also triggered numerous landslides, which contributed to widespread destruction of many small villages. For example, the eruption at Tolbachik Volcano in Kamchatka Russia triggered a response in the Earth Observing Mission-1 EO-1 and ASTER sensor webs and led to the acquisition of high spatial resolution image data for the next 6 months of the eruption.

Heat flow measured in the SWIR and TIR during the development of one of the largest lava flow fields in the last 50 years, combined with digital elevation models, constrained models of future lava flows. Changes in the color of volcanic lakes and the health of nearby ecosystems over time can signal changes in the flux or species of degassing, which are critical to detect both prior to and following an eruption.

Length and time scales over which responses should be quantified: The data scales spatial, spectral, temporal and wavelength region required are directly related to the measured volcanic property. Data acquired at even higher frequencies are essential for hazard mitigation e. Such data have been used to measure changes in the eruptive products over time e.

To maximize their utility to society, all of these space-based observations need to be rapidly downlinked following acquisition.

Priority—Very Important: Monitoring the ground motion following a large earthquake would improve understanding of how the crust accommodates the stresses imposed through a combination of continued slip on faults, viscoelastic relaxation, and flow of crustal fluids.

Identifying the correct mechanism for relaxation is critical for understanding how a fault heals and prepares for the next event. Coseismic models based on GPS, InSAR, seismic waves, and high-resolution optical imagery are used to estimate the immediate change in crustal stress surrounding the rupture zone.

Frequent and accurate measurements of postseismic deformation will reveal the rheological properties of the crust and upper mantle.

More importantly, measuring the evolution of the deformation after an earthquake provides a window into stress increases on surrounding faults. High spatial resolution optical difference maps as well as InSAR decorrelation maps can be used to identify areas of destroyed infrastructure associated with coseismic events.

Relevant quantities: The relevant quantities to be measured are similar to the quantities need for Objective S-1b. These are crustal deformation surrounding the fault from InSAR, seismometers, and GPS; temporal variations in gravity, which can reveal large-scale offshore deformation not observable by other methods; and high-resolution, bare-earth topography, which can reveal the repeated deformations over many earthquake cycles.

Length and time scales over which responses should be quantified: Postseismic processes are strongest immediately following an earthquake and typically decay logarithmically with time. Over the time period of 6 months to 10 years following a major rupture, far-field km from the fault and synoptic gravity measurements become more important for monitoring viscoelastic processes.

Linkages of S-2 Objectives to Other Panels and Integrating Themes Responses to disruptive, extreme geological events like earthquakes or volcanic eruptions require both rapid quantification of event characteristics and timely dissemination of those data.

Priority—Most Important: Sea-level change arises from a combination of ocean volume changes thermal expansion or contraction of seawater , mass input from the cryosphere, ocean and atmosphere dynamics, gravitational changes, and vertical land motion.

The global ice sheets contain the greatest potential for rapid sea-level rise in the coming decades. The most rapid accelerations in sea level over the last decade derive from ice sheets, particularly Greenland. Change in Antarctica has the greatest potential to cause sea-level rise in North America in the coming century.

To project future sea-level rise, it is necessary to first quantify the current rate of global mean sea-level rise as well as the relative contributions of the driving processes. Achieving this objective requires both observations of the global sea-surface height and the changing ice sheets. The sea-surface height varies regionally at significantly higher rates than the global mean for periods of several years to several decades owing to changes in the winds and ocean circulation e.

Relevant quantities: Sea-surface height has been measured using satellite radar altimeters e. Precise sea-surface height measurements also require geodetic-quality GPS receivers for orbits, microwave radiometers to correct for water-vapor path delays, dual frequencies for ionospheric corrections, and a stable and well-defined terrestrial reference frame GPS, SLR, VLBI. Maintaining the global tide gage network is required to detect biases and drift.

Observations needed to understand ice-sheet contributions to sea level include ice thickness the difference between the ice-sheet topography and the bedrock topography for ice-sheet models, seasonal and interannual ice velocities, time-variable gravity, ice topography and its change, FIGURE Length and time scales over which responses should be quantified: Sea surface height is measured with good precision 2 cm root mean square [RMS] accuracy at km resolution.

The current temporal and spatial resolution for altimetry in the deep ocean is sufficient, but improving the resolution to 10 km in coastal waters would better enable the study of dynamical sea-surface height changes, which are different in shallow, coastal waters than in the deep ocean owing to interactions with bathymetry.

Measurements over ice sheets ice thickness, ice velocity, ice topography change, surface melt need to be made continuously over decades to detect and understand potentially rapid changes. The time sampling can be monthly or less , and the spatial resolution will depend on the measurement objectives. The spatial resolution of ice thickness near the grounding line needs to be less than m, the spatial resolution of ice-topography change needs to be better than m, and the spatial resolution of ice velocity needs to be better than m.

Priority—Most Important: The influence of vertical land motion on local sea-level rise is profound but poorly constrained. Vertical land motion is driven by natural and anthropogenic processes ranging from changes in the mass load, isostatic and nonisostatic adjustment of the solid Earth in response to changes in loading ice, water, sediment , sediment compaction, extraction of fluids oil, gas, and water from underground reservoirs, and tectonics.

Currently, vertical land motion is not regularly measured in most areas. Where it has been measured, we now know that land subsidence can be more than an order of magnitude greater than sea-surface elevation changes owing to ocean mass changes and thermal expansion or contraction Figure