NASA Missions to Enable Critical Solid Earth Science Observations

+----------------+----------------+--------------------+---------------+
| Science        | Information    | Observation Needs  | NASA          |
| Questions      | Needs          |                    | Observations  |
+----------------+----------------+--------------------+---------------+
| What is the    | Earth surface  | mm/yr-level 3D     | GPS           |
| nature of      | motion         | surface            |               |
| deformation at | throughout     | deformation        |               |
| plate          | seismic cycle  |                    |               |
| boundaries?    |                |                    |               |
+----------------+----------------+--------------------+---------------+
|                | Subsurface     | -   Subsurface     | -   Boreholes |
|                | c              |     layer location |               |
|                | haracteristics |     and geometry   | -   Seismic   |
|                |                |     to 150 Km      |     arrays    |
|                |                |     depth          |               |
|                |                |                    |               |
|                |                | -   Mechanical     |               |
|                |                |     properties of  |               |
|                |                |     the subsurface |               |
|                |                |     layers         |               |
+----------------+----------------+--------------------+---------------+
|                | Sea floor      | mm/yr-level 3D     | GPS           |
|                | geodesy        | surface            |               |
|                |                | deformation        |               |
+----------------+----------------+--------------------+---------------+
|                | Gravity        | High-accuracy,     | -   Gravity   |
|                | Anomalies      | sub-Km-scale       |               |
|                |                | resolution vector  |  gradiometers |
|                |                | gravity signal     |               |
|                |                |                    | -   Airborne  |
|                |                |                    |               |
|                |                |                    |   gravimeters |
+----------------+----------------+--------------------+---------------+
| How do         | Topography     | 3D surface         | GPS           |
| tectonic,      |                | topography at      |               |
| geomorphic,    |                | various resolution |               |
| climatic, and  |                | scales             |               |
| biologic       |                |                    |               |
| processes      |                |                    |               |
| interact to    |                |                    |               |
| shape the      |                |                    |               |
| landscape and  |                |                    |               |
| create Natural |                |                    |               |
| hazards?       |                |                    |               |
+----------------+----------------+--------------------+---------------+
|                | Topographic    | Mm/yr level 3D     | GPS           |
|                | change         | surface            |               |
|                |                | deformation        |               |
+----------------+----------------+--------------------+---------------+
|                | Subsurface     | -   Subsurface     | -   Boreholes |
|                | c              |     layer location |               |
|                | haracteristics |     and geometry   | -   Seismic   |
|                |                |     to 150 Km      |     arrays    |
|                |                |     depth          |               |
|                |                |                    |               |
|                |                | -   Mechanical     |               |
|                |                |     properties of  |               |
|                |                |     the subsurface |               |
|                |                |     layers         |               |
+----------------+----------------+--------------------+---------------+
|                | Surface        | Geometric,         | Field         |
|                | materials      | electrical,        | observations  |
|                |                | thermal properties |               |
+----------------+----------------+--------------------+---------------+
|                | Weather and    | -   Rainfall       | Met stations  |
|                | climate        |     amount and     |               |
|                |                |     rate           | Rain guages   |
|                |                |                    |               |
|                |                | -   Soil moisture  |               |
+----------------+----------------+--------------------+---------------+
|                | Vegetation     | -   Vegetation     |               |
|                | properties     |     classes        |               |
|                |                |                    |               |
|                |                | -   Vegetation     |               |
|                |                |     biomass change |               |
+----------------+----------------+--------------------+---------------+
|                | Surface ages   | -   Rate of        | Manual field  |
|                |                |     deposition     | surface aging |
|                |                |                    |               |
|                |                | -   Rate of        |               |
|                |                |     exhumation     |               |
+----------------+----------------+--------------------+---------------+
| What are the   | Ice surface    | Sub-meter 3D       | -   GPS       |
| interactions   | topography     | surface topography |               |
| among ice      |                |                    | -   Airborne  |
| masses,        |                |                    |     laser     |
| oceans, and    |                |                    |     altimeter |
| the solid      |                |                    |               |
| Earth and      |                |                    |               |
| their          |                |                    |               |
| implications   |                |                    |               |
| for sea level  |                |                    |               |
| rise?          |                |                    |               |
+----------------+----------------+--------------------+---------------+
|                | Ice flow       | m/yr vector ice    | GPS           |
|                | velocity       | velocity           |               |
+----------------+----------------+--------------------+---------------+
|                | Ice volume,    | 10-m accuracy ice  | Boreholes     |
|                | bed conditions | thickness          |               |
+----------------+----------------+--------------------+---------------+
|                | Ice mass flux  | -   Above three    |               |
|                |                |     observations   |               |
|                |                |                    |               |
|                |                | -   Time-varying   |               |
|                |                |     gravity to     |               |
|                |                |     500-Km         |               |
+----------------+----------------+--------------------+---------------+
|                | Snow/ice       | -   Sub-Km snow    |               |
|                | albedo         |     location and   |               |
|                |                |     extent         |               |
|                |                |                    |               |
|                |                | -   Surface        |               |
|                |                |     optical        |               |
|                |                |     reflectivity   |               |
|                |                |                    |               |
|                |                | -   Surface        |               |
|                |                |     microwave      |               |
|                |                |     emissivity     |               |
+----------------+----------------+--------------------+---------------+
|                | Ocean salinity | Surface microwave  |               |
|                |                | emissivity         |               |
+----------------+----------------+--------------------+---------------+
|                | Sea ice cover  | \<50m ice location |               |
|                |                | and extent         |               |
+----------------+----------------+--------------------+---------------+
|                | Coastal        | \<10m resolution   |               |
|                | boundary       | coastline location |               |
|                | changes        | and properties     |               |
+----------------+----------------+--------------------+---------------+

+----------------+----------------+--------------------+---------------+
| Science        | Information    | Observation Needs  | NASA          |
| Questions      | Needs          |                    | Observations  |
+----------------+----------------+--------------------+---------------+
| How do         | Surface motion | mm/yr-level 3D     | GPS           |
| magmatic       | of volcanoes   | surface            |               |
| system evolve, |                | deformation        |               |
| and under what |                |                    |               |
| conditions do  |                |                    |               |
| they erupt?    |                |                    |               |
+----------------+----------------+--------------------+---------------+
|                | Subsurface     | -   Subsurface     | -   Boreholes |
|                | c              |     layer location |               |
|                | haracteristics |     and geometry   | -   Gravity   |
|                |                |     to 150 Km      |               |
|                |                |     depth          |  gradiometers |
|                |                |                    |               |
|                |                | -   Mechanical     | -   Airborne  |
|                |                |     properties of  |               |
|                |                |     the subsurface |   gravimeters |
|                |                |     layers         |               |
+----------------+----------------+--------------------+---------------+
|                | seismicity     | 0-15 Km subsurface | -   Seismic   |
|                |                | layer location     |     arrays    |
|                |                |                    |               |
|                |                |                    | -   boreholes |
+----------------+----------------+--------------------+---------------+
|                | Silica content | Silica content of  | Field         |
|                | of Magma       | crystaline rocks   | observations  |
+----------------+----------------+--------------------+---------------+
|                | Gas emission   | Thermal changes to | Field         |
|                | rate           | 0.5K               | observations  |
+----------------+----------------+--------------------+---------------+
|                | Time-series    | -   Thermal        |               |
|                | thermal        |     changes to 0.5 |               |
|                | changes        |     K              |               |
|                |                |                    |               |
|                |                | -   Temperature to |               |
|                |                |     0.5K           |               |
+----------------+----------------+--------------------+---------------+
|                | Ionospheric    | Changes in         |               |
|                | changes        | electric field     |               |
+----------------+----------------+--------------------+---------------+
|                | Gravity        | High-accuracy,     | -   Gravity   |
|                | Anomalies      | sub-Km-scale       |               |
|                |                | resolution vector  |  gradiometers |
|                |                | gravity signal     |               |
|                |                |                    | -   Airborne  |
|                |                |                    |               |
|                |                |                    |   gravimeters |
+----------------+----------------+--------------------+---------------+
|                | Plume/ash      | -   Distinguish    | Field         |
|                | properties     |     ash and met    | observations  |
|                |                |     cloud          |               |
|                |                |                    |               |
|                |                | -   Thermal        |               |
|                |                |     changes to     |               |
|                |                |     0.3K           |               |
|                |                |                    |               |
|                |                | -   Co2 Column     |               |
|                |                |     abundance to   |               |
|                |                |     0.5g/m2        |               |
+----------------+----------------+--------------------+---------------+
|                | topography     | -   10-cm level    | -   GPS       |
|                |                |     topography     |               |
|                |                |                    | -   Airborne  |
|                |                |                    |     InSAR     |
+----------------+----------------+--------------------+---------------+
|                | Surface        | -   m/s level flow | Field         |
|                | charateristics |     velocity       | observations  |
|                |                |                    |               |
|                |                | -   1K level flow  |               |
|                |                |     temperature    |               |
|                |                |                    |               |
|                |                | -   roughness and  |               |
|                |                |     topography     |               |
+----------------+----------------+--------------------+---------------+
|                | Post-eruption  | -   m/s level flow | Field         |
|                | flow type      |     velocity       | observations  |
|                |                |                    |               |
|                |                | -   1K level flow  |               |
|                |                |     temperature    |               |
|                |                |                    |               |
|                |                | -   roughness and  |               |
|                |                |     topography     |               |
+----------------+----------------+--------------------+---------------+
| What are the   | Post-glacial   | -   mm/yr 3D       | -   GPS       |
| dynamics of    | relaxation     |     surface        |               |
| the mantle and |                |     deformation    | -   Gravity   |
| crust, and how |                |                    |               |
| does the       |                | -   Secular        |  gradiometers |
| Earth's        |                |     ime-varying    |               |
| surface        |                |     gravity        | -   Airborne  |
| respond?       |                |                    |               |
|                |                | -   High-accuracy  |   gravimeters |
|                |                |     few-km vector  |               |
|                |                |     gravity        |               |
+----------------+----------------+--------------------+---------------+
|                | Post-seismic   | -   mm/yr 3D       | -   GPS       |
|                | relaxation     |     surface        |               |
|                |                |     deformation    | -   boreholes |
|                |                |                    |               |
|                |                | -   paleofeature   |               |
|                |                |     location to mm |               |
|                |                |     accuracy       |               |
|                |                |                    |               |
|                |                | -   Mechanical     |               |
|                |                |     properties of  |               |
|                |                |     the subsurface |               |
|                |                |     layers         |               |
+----------------+----------------+--------------------+---------------+
|                | Crustal loads  | -   mm/yr 3D       | -   GPS       |
|                |                |     surface        |               |
|                |                |     deformation    | -   Gravity   |
|                |                |                    |               |
|                |                | -   High-accuracy  |  gradiometers |
|                |                |     few-km vector  |               |
|                |                |     gravity        | -   Airborne  |
|                |                |                    |               |
|                |                |                    |   gravimeters |
+----------------+----------------+--------------------+---------------+
|                | Surface        | -   mm/yr 3D       | -   GPS       |
|                | displacements  |     surface        |               |
|                |                |     deformation    | -   Gravity   |
|                |                |                    |               |
|                |                | -   Secular        |  gradiometers |
|                |                |     ime-varying    |               |
|                |                |     gravity        | -   Airborne  |
|                |                |                    |               |
|                |                |                    |   gravimeters |
+----------------+----------------+--------------------+---------------+
|                | Changes in     | -   Secular        | -   Gravity   |
|                | gravity        |     ime-varying    |               |
|                |                |     gravity        |  gradiometers |
|                |                |                    |               |
|                |                | ```{=html}         | -   Airborne  |
|                |                | <!-- -->           |               |
|                |                | ```                |   gravimeters |
|                |                | -   High-accuracy  |               |
|                |                |     few-km vector  |               |
|                |                |     gravity        |               |
+----------------+----------------+--------------------+---------------+
|                | Length of day  | Earth rotation to  | VLBI          |
|                |                | \<marcsec          |               |
+----------------+----------------+--------------------+---------------+
|                | Solid Earth    | -   High-accuracy  | -   Gravity   |
|                | tides          |     few-km vector  |               |
|                |                |     gravity        |  gradiometers |
|                |                |                    |               |
|                |                | -   Earth rotation | -   Airborne  |
|                |                |     to \<marcsec   |               |
|                |                |                    |   gravimeters |
|                |                | -   Earth          |               |
|                |                |     orientation to |               |
|                |                |     \<marcsec      |               |
+----------------+----------------+--------------------+---------------+
| What are the   | Crustal &      | -   Vector mag     | Dense mag     |
| dynamics of    | lithospheric   |     field          | observation   |
| the Earth's    | field          |                    | network       |
| maagnetic      | measurements   | -                  |               |
| field and its  |                |   Short-wavelength |               |
| interaction    |                |     mag gradient   |               |
| with the Earth |                |                    |               |
| system?        |                | -   Few-Km         |               |
|                |                |     resolution     |               |
|                |                |     Electron       |               |
|                |                |     density        |               |
|                |                |     profiles       |               |
|                |                |                    |               |
|                |                | -   High-res       |               |
|                |                |     electric field |               |
+----------------+----------------+--------------------+---------------+
|                | Core field     | -   Vector mag     | -   Dense mag |
|                | strength and   |     field          |               |
|                | secular        |                    |   observation |
|                | changes        | -   Few-nT level   |     network   |
|                |                |     external field |               |
|                |                |                    | -             |
|                |                |                    |  Ground-based |
|                |                |                    |     E-field   |
|                |                |                    |               |
|                |                |                    |  measurements |
+----------------+----------------+--------------------+---------------+
|                | Electrical     | -   Vector mag     | -   Dense mag |
|                | conductivity   |     field          |               |
|                |                |                    |   observation |
|                |                | -   Few-nT level   |     network   |
|                |                |     external field |               |
|                |                |                    | -             |
|                |                | -   Few-Km         |  Ground-based |
|                |                |     resolution     |     E-field   |
|                |                |     Electron       |               |
|                |                |     density        |  measurements |
|                |                |     profiles       |               |
|                |                |                    |               |
|                |                | -   High-res       |               |
|                |                |     electric field |               |
+----------------+----------------+--------------------+---------------+
|                | Length of day  | Earth rotation to  | VLBI          |
|                |                | 1ms                |               |
+----------------+----------------+--------------------+---------------+