Analysing satellite data to track Earth movements

Aotearoa New Zealand is a geologically active country. We feel the big jolts from earthquakes, but there are some minute Earth movements that we didn’t know were taking place beneath our feet until a couple of decades ago. Slow slips are very, very slow movements – just a few millimetres over days, weeks or months.

These small movements are monitored by a network of very sensitive GPS instruments placed around the country and the Chatham Islands. Satellites send microwave signals to the GPS receivers at these sites, enabling them to record very precise positions on the Earth’s surface. This continuous sending and receiving of data allows scientists to measure even the smallest of movements. Scientists are interested in slow slips because the small movements relieve stress in some fault lines but increase stress in others. They want to know how slow slip earthquakes and normal earthquakes are related.

This activity uses actual data from the Institute of Geological and Nuclear Sciences (GNS Science), which shows small slip Earth movements near the East Coast’s Māhia Peninsula. It is part of a suite of activities that support the Build a satellite interactive. These activities support students to engage with the science capabilities ‘Gather and interpret data’, ‘Critique evidence’ and ‘Interpret representations’.

By the end of this activity, students should be able to:

• discuss why scientists have established a monitoring system to track slow slip earthquakes
• discuss how GPS instruments and satellites are used to track very small Earth movements
• use their science capabilities to explore information about monitoring sites and the data they collect.

Download the Word file (see link below).