South America EQ Report Week 2 JANUARY 26

Map of South America’s Seismicity and Plate Boundaries Source: "Seismotectonics of South America (Nazca

Background of South America’s Plate Boundaries Subduction of the Nazca plate: The South America

This Week in Seismic News… According to the ANSS Catalog, there have been a

Sources "ANSS Catalog Search. " ANSS Catalog Search. Northern California Earthquake Data Center, n.

Slides: 5

Download presentation

South America EQ Report, Week 2 JANUARY 26, 2016 OLIVIA HELPRIN

Map of South America’s Seismicity and Plate Boundaries Source: "Seismotectonics of South America (Nazca Plate Region). " Seismicity of the Earth 1900– 2013. US Geologic Survey, 2014. Web. 26 Jan. 2016. <http: //pubs. usgs. gov/of/2015/1031/e/pdf/of 20 15 -1031 -E. pdf>.

Background of South America’s Plate Boundaries Subduction of the Nazca plate: The South America plate’s west margin overrides the Nazca plate, forming a convergent plate boundary. According to the USGS, “the Nazca plate moves slightly north of eastwards at a rate varying from approximately 80 mm/yr in the south, to approximately 65 mm/yr in the north. ” This subduction is responsible for the majority of the tectonic activity experienced in South America. In addition to shallow (0– 70 km), intermediate (70 -300 km) and great (~600 km) depth earthquakes, active volcanic chains are present along South America’s west coast due to the melting of the Nazca plate’s lithosphere in locations of intermediate to great depth subduction. Chilean Triple Junction: This region “represents the only presently active ridge-trench collision where the overriding plate is composed of continental lithosphere” (Lewis). This is the site of the largest earthquake ever recorded, with a 9. 8 magnitude in 1960. Source: Lewis, Steve. "Offshore Earthquakes and Landslides. " SOPAC. USGS, n. d. Web. 26 Jan. 2016. <https: //walrus. wr. usgs. gov/earthquakes/sopac. html>.

This Week in Seismic News… According to the ANSS Catalog, there have been a series of 19 earthquakes with magnitudes ranging between 4. 00 - 5. 00 within the last week (1/19 -26/2016). These earthquakes range from 7 – 205 km deep. All occurred along the north-central western coast of South America (between -68. 5009 to 88. 8323 degrees longitude and 6. 8073 to -32. 6255 degrees latitude). The largest earthquakes, with magnitudes of 5. 00, occurred on January 19 th and 20 th within similar localities: January 19 th: (-14. 0753, -72. 8806), 48. 17 km deep January 20 th: (-15. 8792, -74. 0797), 47. 03 km deep

Sources "ANSS Catalog Search. " ANSS Catalog Search. Northern California Earthquake Data Center, n. d. Web. 26 Jan. 2016. "Seismotectonics of South America (Nazca Plate Region). " Seismicity of the Earth 1900 – 2013. US Geologic Survey, 2014. Web. 26 Jan. 2016. <http: //pubs. usgs. gov/of/2015/1031/e/pdf/of 2015 -1031 -E. pdf>. Lewis, Steve. "Offshore Earthquakes and Landslides. " SOPAC. USGS, n. d. Web. 26 Jan. 2016. <https: //walrus. wr. usgs. gov/earthquakes/sopac. html>. "South America - Earthquakes and Tectonics. " IRIS -. N. p. , n. d. Web. 26 Jan. 2016. <https: //www. iris. edu/hq/programs/education_and_outreach/animations/35>. "Chile Margin and Triple Junction Geology. " NOAA Ocean Explorer Podcast RSS. N. p. , n. d. Web. 26 Jan. 2016. <http: //oceanexplorer. noaa. gov/explorations/10 chile/background/geology. html>.