Measuring Ground Motion with GPS: How GPS Works part of Geodesy:Activities
Shelley E Olds, EarthScope Consortium
With printouts of typical GPS velocity vectors found near different tectonic boundaries and models of a GPS station, demonstrate how GPS work to measure ground motion.GPS velocity vectors point in the direction that a GPS station moves as the ground it is anchored to moves. The length of a velocity vector corresponds to the rate of motion. GPS velocity vectors thus provide useful information for how Earth's crust deforms in different tectonic settings.

Converging Tectonic Plates Demonstration part of Geodesy:Activities
Shelley E Olds, EarthScope Consortium
During this demo, participants use springs and a map of the Pacific Northwest with GPS vectors to investigate the stresses and surface expression of subduction zones, specifically the Juan de Fuca plate diving beneath the North American plate.

Tsunami Early Warning Demonstration part of Geodesy:Activities
Shelley E Olds, EarthScope Consortium
This hands-on demonstration illustrates how instruments can be used to warn people of a tsunami. The same principles can be applied to earthquake early warning. With an older audience, this is a demonstration that can be used to start a conversation. With a younger audience, this activity is a game.

Pinpointing Location with GPS Demonstration: How GPS Works (Part 2) part of Geodesy:Activities
Shelley E Olds, EarthScope Consortium
Using string, bubble gum, and a model of a GPS station, demonstrate how GPS work to pinpoint a location on Earth.Precisely knowing a location on Earth is useful because our Earth's surface is constantly changing from earthquakes, volcanic eruptions, tectonic plate motion, landslides, and more. Thus, scientists can use positions determined with GPS to study all these Earth processes.

Earthquake Early Warning Demonstration part of Geodesy:Activities
Shelley E Olds, EarthScope Consortium
This hands-on demonstration illustrates how GPS instruments can be used in earthquake early warning systems to alert people of impending shaking. The same principles can be applied to other types of early warning systems (such as tsunami) or to early warning systems using a different type of geophysical sensor (such as a seismometer instead of a GPS).This demo is essentially a game that works best with a large audience (ideally over 30 people) in an auditorium. A few people are selected to be either surgeons, GPS stations, or a warning siren, with everyone else forming an earthquake "wave."

Science with Flubber: Glacial Isostasy part of Geodesy:Activities
Shelley E Olds, EarthScope Consortium
Using two sets of flubber, one representing the Earth and one representing a glacier, demonstrate how the crust sinks and rebounds to the weight of a glacier, and how this motion can be measured using GPS.Flubber is a rubbery elastic substance, a non-Newtonian elasco-plastic fluid, that flows under gravity, but breaks when under high stress. Flubber is useful for demonstrating a wide range of Earth and glacier processes.