Geobulletin alpha

Source info:

Author:
Date:	2014-04-02 14:53:14
Blog:	About Geology
URL:	http://geology.about.com/b/2014/04/02/chile-earthquake-fills-the-rack.htm

Summary:

Yesterday's magnitude 8.2 earthquake off the coast of northern Chile was significant to scientists because it was widely anticipated and because it filled the largest remaining "seismic gap" in a large swatch of the South American subduction zone. This map (and one like it at Cornell University) shows the rupture zones of historic earthquakes. The area of yesterday's event matched a large earthquake in 1877. We now appear to have a full set of quakes rupturing this part of the boundary between the South America and Nazca plates. It's still not clear how much meaning there is to a "seismic gap." The gaps are a reverse way of looking at "fault segments," which are distinct sections of plate boundaries that appear to define typical earthquakes, because earthquakes aren't tidy things that know their places. The Tohoku quake of 2011 spilled across several "segments" of the Japan subduction zone. There's no guarantee that yesterday's quake has "prevented" a giant magnitude-9 event that would encompass several of the Chilean segments. But that's for the experts to discuss, and they already are. Other highlights of the quake worth visiting: The hydracoustic station at Robinson Crusoe Island recorded the quake's sound The IRIS Consortium has a "Teachable Moment" feature on the quake Austin Elliott's Trembling Earth blog gathers a lot of good links Deutsches GeoForschungsZentrum GFZ image

Content analysis:

Geographic context:

Location	Country	Latitude	Longitude
Chile	CL	-35.7052	-71.3411
Japan	JP	37.4876	139.838
United States	US	37.1679	-95.845
South America		-23.0301	-67.9037
Robinson Crusoe Island	US	42.5076	-92.3543
Cornell University	US	42.4475	-76.4827

Keywords:

, area, Austin Elliott, boundary, Chile Earthquake, Chilean segments, coast, Cornell University, Deutsches GeoForschungsZentrum GFZ, distinct sections, experts, fault segments, gaps, gathers, giant magnitude-9 event, good links, guarantee, historic earthquakes, hydracoustic station, IRIS Consortium, Japan subduction zone, large earthquake, large swatch, map, Nazca plates, northern Chile, plate boundaries, reverse way, Robinson Crusoe Island, rupture zones, scientists, seismic gap, set, South American subduction, subduction zone, Teachable Moment, things, Tohoku quake, Trembling Earth blog, typical earthquakes