| Timestamp: | 1970-07-31 17:08:05 |
| Isc-Event: | 794176 |
| Anss-Url: | iscgem794176 |
| Local-Time: | 12:08:05 |
| Magnitude: | 8.0 |
| Depth: | 6450NaN0 |
| Location: | -1.6°N -72.53°W |
| Countries Affected: | Colombia |
| Casualties: | 1 dead, several injured |
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. Its depth forestalled more serious casualties,[1] and there were no aftershocks.[2]
The depth of the earthquake prompted scientists in South America to install seismometer networks focused on long-period earthquakes.[1] Until the 1994 Bolivia earthquake, the 1970 Colombia earthquake was famous among seismologists as the largest deep earthquake.[3]
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;[4] this was released to great controversy.[3] 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.[5] 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.[3]