The ground under Ulaanbaatar, Mongolia — measured by the Global Seismographic Network (IRIS/USGS) station IU ULN 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 |
|---|---|---|---|
| M5.1 | 263 km WSW of Yanglong, China | 1970-01-01 00:00 UTC | 1,443 km |
| M4.7 | 132 km E of Wuwei, China | 1970-01-01 00:00 UTC | 1,106 km |
| M4.6 | 18 km S of Guyuan, China | 1970-01-01 00:00 UTC | 1,339 km |
| M4.6 | 63 km W of Bayan Hot, China | 1970-01-01 00:00 UTC | 1,019 km |
| M4.5 | 270 km S of Dunhuang, China | 1970-01-01 00:00 UTC | 1,476 km |
| M4.3 | 1970-01-01 00:00 UTC | 1,368 km | |
| M4.2 | 1970-01-01 00:00 UTC | 623 km |
| Mag | Where | When | Distance |
|---|---|---|---|
| M7.7 | 12 km WSW of Pitaloza Arriba, Panama | 1970-01-01 00:00 UTC | 13,801 km |
| M7.0 | 191 km ENE of Nagqu, China | 1970-01-01 00:00 UTC | 2,052 km |
| M6.9 | 76 km NE of Ozernovskiy, Russia | 1970-01-01 00:00 UTC | 3,551 km |
| M6.9 | 197 km WNW of Port-Olry, Vanuatu | 1970-01-01 00:00 UTC | 8,984 km |
| M6.8 | central Mid-Atlantic Ridge | 1970-01-01 00:00 UTC | 12,658 km |
| M6.7 | central Mid-Atlantic Ridge | 1970-01-01 00:00 UTC | 12,634 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.