The ground under Salta, Argentina — measured by the GEOFON network (GFZ Potsdam) station GE SALTA 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 |
|---|---|---|---|
| M5.3 | 28 km SSW of Camaná, Peru | 1970-01-01 00:00 UTC | 1,061 km |
| M5.1 | 72 km SSW of Colchane, Chile | 1970-01-01 00:00 UTC | 542 km |
| M4.9 | 16 km WSW of La Tirana, Chile | 1970-01-01 00:00 UTC | 590 km |
| M4.9 | 100 km E of La Tirana, Chile | 1970-01-01 00:00 UTC | 495 km |
| M4.8 | 23 km SW of San Antonio, Chile | 1970-01-01 00:00 UTC | 1,182 km |
| M4.7 | 42 km W of Ollagüe, Chile | 1970-01-01 00:00 UTC | 409 km |
| M4.7 | 46 km WNW of Ollagüe, Chile | 1970-01-01 00:00 UTC | 424 km |
| M4.7 | 94 km NNW of Coquimbo, Chile | 1970-01-01 00:00 UTC | 775 km |
| M4.7 | 19 km NE of Atico, Peru | 1970-01-01 00:00 UTC | 1,170 km |
| M4.7 | 39 km SSW of Serrezuela, Argentina | 1970-01-01 00:00 UTC | 753 km |
| Mag | Where | When | Distance |
|---|---|---|---|
| M7.7 | 12 km WSW of Pitaloza Arriba, Panama | 1970-01-01 00:00 UTC | 3,869 km |
| M7.0 | 191 km ENE of Nagqu, China | 1970-01-01 00:00 UTC | 17,873 km |
| M6.9 | 76 km NE of Ozernovskiy, Russia | 1970-01-01 00:00 UTC | 15,221 km |
| M6.9 | 197 km WNW of Port-Olry, Vanuatu | 1970-01-01 00:00 UTC | 12,955 km |
| M6.8 | central Mid-Atlantic Ridge | 1970-01-01 00:00 UTC | 5,699 km |
| M6.7 | central Mid-Atlantic Ridge | 1970-01-01 00:00 UTC | 5,692 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.