1970 Colombia earthquake

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1970 Colombia earthquake is located in Colombia
1970 Colombia earthquake
Date July 31, 1970 (1970-07-31)
Magnitude 7.6 Mw[1]
Depth 651 km (405 mi)
Epicenter 1°28′S 72°34′W / 1.46°S 72.56°W / -1.46; -72.56Coordinates: 1°28′S 72°34′W / 1.46°S 72.56°W / -1.46; -72.56
Areas affected Colombia
Casualties 1

The 1970 Colombia earthquake occurred in Colombia on July 31.

Details and aftermath[edit]

The earthquake hit at 17:08 UTC on July 31, 1970.[2] It registered 8.0 on the Richter scale, and it killed one person, injuring multiple others. Because it had a depth of 651 km (405 mi), it spread over an extensive area and caused shaking in San Juan, Bogotá, Caracas, Buenos Aires, and São Paulo; it was felt as far north as Mexico City.[2] Its depth forestalled more serious casualties,[2] and there were no aftershocks.[3]

The depth of the earthquake prompted scientists in South America to install seismometer networks focused on long-period earthquakes.[2] Until the 1994 Bolivia earthquake, the 1970 Colombia earthquake was famous among seismologists as the largest deep earthquake.[4]

Analysis[edit]

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;[5] this was released to great controversy.[4] 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.[6] In 1997, Russakoff, Ekstrom, and Trump 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.[4]

References[edit]

  1. ^ IISEE. "IISEE Catalogue Search parameters page". Catalog of Damaging Earthquakes in the World. Retrieved August 18, 2013. 
  2. ^ a b c d "Historic Earthquakes: Colombia 1970". United States Geological Survey. November 1, 2012. Retrieved July 30, 2013. 
  3. ^ Karato, pg. 162.
  4. ^ a b c Russakoff, Ekstrom, and Trump, pg. 20423.
  5. ^ Kennett and Simons, pg. 471.
  6. ^ Russakoff, Ekstrom, and Trump, pg. 20424.

Sources[edit]