Plotting recent earthquakes and volcanoes to find the plate boundaries

The idea

Earthquakes and volcanoes are not scattered at random; plotted on a map they trace narrow belts, and those belts are the plate boundaries.

What you need

• a CSV of the last 30 days of magnitude 5 and above earthquakes from the USGS earthquake catalogue search (latitude, longitude, depth, magnitude), or the Geoscience Australia earthquakes portal for Australian events
• a blank world map with a 10 degree grid (A3) or a spreadsheet map chart
• coloured pencils: three colours for depth bands 0 to 70 km, 70 to 300 km, over 300 km
• a plate boundary map (USGS This Dynamic Earth) kept hidden until step 4

How to do it

1. Download the catalogue and sort by magnitude; plot every event as a dot coloured by depth band.
2. Add the locations of ten recently active volcanoes from a class list (the teacher supplies names and coordinates from the Geoscience Australia or USGS resources).
3. Describe the pattern: where the dots crowd, where the deep dots lie relative to the shallow ones, and where the map is empty.
4. Overlay the plate boundary map and test the description: what fraction of the dots lie within about 5 degrees of a boundary; which boundaries have deep earthquakes.
5. Locate Australia's own events from the Geoscience Australia portal and explain why they sit inside a plate rather than on its edge.

What you should see

The dots form narrow belts around the Pacific rim, along the Alpine-Himalayan chain and along mid-ocean ridges, with most of the map empty; where plates subduct around the Pacific rim the earthquakes get deeper with distance from the ocean trench, on the side of the overriding plate, tracing the plate that sinks beneath it, and the deepest (over 300 km) lie furthest from the trench, while ridge earthquakes are all shallow. Volcanoes fall on the same belts. Most magnitude 5 and above events of any month fall within a few degrees of a boundary on the overlay; Australia's events (the portal lists them) sit inside the plate and are shallow. The learner knows it worked when the belts drawn from the dots alone match the overlay's boundaries.

What changes

What you change

location (latitude, longitude)

What you measure

frequency and depth of earthquakes

What you keep the same

• time window
• magnitude threshold

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

• Earthquakes happen anywhere at random.
• Australia has no earthquakes; it has many shallow intraplate earthquakes, including the 1989 Newcastle event.
• Volcanoes and earthquakes are unrelated hazards; they share the same boundaries.

Safety card

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

• Science 7-10 Syllabus (2023), NSW Education Standards Authority (implemented from 2026; codes read at curriculum.nsw.edu.au on 22 and 23 September 2026)SC4-CHG-01SC4-DA1-01SC4-WS-05SC4-WS-06
• Australian Curriculum v9AC9S8U03AC9S8I04AC9S8I05AC9S8I07

Sources

The pages the author read to write this activity.

1. curriculum.nsw.edu.au/learning-areas/science/science-7-10-2023/outcomes
2. vocabulary.curriculum.edu.au/MRAC/2024/04/LA/SCI/export/MRAC/2024/04/LA/SCI.jsonld
3. www.ga.gov.au/education/classroom-resources/analysis-of-earthquakes-using-real-map-and-data-sets
4. earthquake.usgs.gov/earthquakes/search
5. earthquakes.ga.gov.au
6. pubs.usgs.gov/gip/dynamic/understanding.html