  | |
| UTC time | 1970-07-31 17:08:05 |
|---|---|
| ISC event | 794176 |
| USGS-ANSS | ComCat |
| Local date | July 31, 1970 |
| Local time | 12:08:05 |
| Magnitude | 8.0 Mw [1] |
| Depth | 645 km (401 mi) [1] |
| Epicenter | 1°36′S 72°32′W / 1.6°S 72.53°W [1] |
| Areas affected | Colombia |
| Max. intensity | IV (Light) |
| Casualties | 1 dead, several injured [2] |
The 1970 Colombia earthquake occurred in Colombia on July 31.
The shock killed one person and injured several others. Because it was a deep-focus earthquake, shaking occurred over an extensive area, including San Juan, Bogotá, Caracas, Buenos Aires, and São Paulo; it was felt as far north as Mexico City.[3] Its depth forestalled more serious casualties,[3] and there were no aftershocks.[4]
The depth of the earthquake prompted scientists in South America to install seismometer networks focused on long-period earthquakes.[3] Until the 1994 Bolivia earthquake, the 1970 Colombia earthquake was famous among seismologists as the largest deep earthquake.[5]
A study completed by Dziewonski and Gilbert (1974) determined that the earthquake had featured isotropic compression, or an increase in density near the rupture point similar to an implosion;[6] this was released to great controversy.[5] They also claimed that the compression had been initiated 80 seconds before the actual earthquake's short-period shaking. Many studies have reached differing conclusions including a dearth of isotropic movement, and many scientists feel that resolution created errors in Dziewonski and Gilbert's findings.[7] In 1997, Russakoff, Ekstrom, and Tromp reassessed their findings utilizing more advanced equipment that factored in shear wave splitting and coupling (the measure of how tightly locked two sides of a fault or plate are) and confirmed that there was very little isotropic compression.[5]
