The ground under Grafenberg, Germany — measured by the Global Seismographic Network (IRIS/USGS) station IU GRFO and redrawn here every 15 minutes. A thin band means a quiet ground; a tall spike is a passing earthquake, near or on the other side of the planet.
| Mag | Where | When | Distance |
|---|---|---|---|
| M5.7 | 61 km WNW of Leni, Italy | 1970-01-01 00:00 UTC | 1,242 km |
| M5.2 | 50 km WNW of Malfa, Italy | 1970-01-01 00:00 UTC | 1,238 km |
| M4.9 | 81 km NNW of Malfa, Italy | 1970-01-01 00:00 UTC | 1,191 km |
| M4.9 | 53 km WNW of Leni, Italy | 1970-01-01 00:00 UTC | 1,243 km |
| M4.7 | 52 km WNW of Malfa, Italy | 1970-01-01 00:00 UTC | 1,234 km |
| M4.6 | 6 km NNE of Sámi, Greece | 1970-01-01 00:00 UTC | 1,473 km |
| M4.5 | 2 km W of Lunca Jariștei, Romania | 1970-01-01 00:00 UTC | 1,216 km |
| M3.1 | 1970-01-01 00:00 UTC | 267 km |
| Mag | Where | When | Distance |
|---|---|---|---|
| M7.7 | 12 km WSW of Pitaloza Arriba, Panama | 1970-01-01 00:00 UTC | 9,507 km |
| M7.0 | 191 km ENE of Nagqu, China | 1970-01-01 00:00 UTC | 6,824 km |
| M6.9 | 76 km NE of Ozernovskiy, Russia | 1970-01-01 00:00 UTC | 8,264 km |
| M6.9 | 197 km WNW of Port-Olry, Vanuatu | 1970-01-01 00:00 UTC | 15,419 km |
| M6.8 | central Mid-Atlantic Ridge | 1970-01-01 00:00 UTC | 6,289 km |
| M6.7 | central Mid-Atlantic Ridge | 1970-01-01 00:00 UTC | 6,249 km |
Waves from a large earthquake reach this station minutes later — up to about 20 minutes from the far side of the Earth. Look for a spike in the helicorder at that time.