Observatories rarely rely on a single sensor. Instead they fuse three independent data streams — seismicity, gas geochemistry, and ground deformation — because each responds to magma movement on a different timescale and can be faked or masked individually. Agreement across all three is what actually raises an alert level.
Before the 1991 Pinatubo eruption, converging seismic swarms, a sharp SO₂ spike, and rapid summit tilt gave scientists just enough lead time to evacuate roughly 60,000 people — one of the most successful eruption forecasts in history.
A 3D cutaway volcano wired with the same instrument types real observatories use — seismometers, an SO₂ gas-sensing plume, and GPS ground-deformation vectors — that respond together as simulated magma pressure rises.
Rising magma pressure inflates the edifice, increases quake frequency at flank seismometers, and boosts SO₂ output in the plume — the three independent signals observatories fuse into a single alert level.
Raise magma pressure to see the volcano bulge, GPS arrows lengthen, and seismic pulses accelerate. Adjust gas flux and seismic gain independently to explore how each instrument type can lead or lag the others.
Before Mount Pinatubo's 1991 eruption, agreement between seismic swarms, an SO₂ spike, and rapid summit tilt let scientists forecast the event and evacuate roughly 60,000 people in time.