This page is the home for data, figures, references that are relevant to the Subduction Factory Initiative and the Seismogenic Experiment (SEIZE) Initiative and Costa Rica-Nicaragua focus area. If you have questions, suggestions, or if you want to submit data, please contact Andreas Aichinger at the MARGINS Office, who will be happy to try to help you.
Click here for more on Centam volcanoes (including pictures!) and geochemical data from Michael Carr's web page at Rutgers University: http://www-rci.rutgers.edu/~carr/index.html
Here are some figures related to Costa Rica-Nicaragua that are of interest. Please click on the thumbnails to see the enlarged version.
Trenches (barbed lines) associated with convergent margins
of the Pacific, Caribbean, and eastern Indian Ocean. Red barbs identify
accreting margins, where the forearc is growing seaward by offscraping
of trench-floor deposits. Yellow barbs are non-accreting margins along
the base of with no modern growth of sedimentary prisms. About 44% of
Earth’s aggregate convergent margin length of 43,000 km is non-accretionary
and about 56% is accretionary. Each year a total of about 1 cubic kilometer
of upper plate material returns to the mantle.
Map of the Central American convergent margin, showing the
location of volcanoes and DSDP site 495 and ODP sites 844 and 1039.
Regional variation in Ba/La in lavas from
along the Central American arc. Ba/La is another monitor for the subduction
component. Filled symbols are samples from along the volcanic front. Open
symbols are back-arc samples. The back-arc samples in Honduras, furthest
from the volcanic front (open triangles), have low Ba/La and are derived
from depleted mantle and lack a subduction signature. Lavas from western
Nicaragua (magenta diamonds) show the maximum slab signal (Ba/La up to
140 compared to normal mantle Ba/La =10-20).
Variations of Ba/Th vs. U/La in lavas from
the volcanic front of Central America. Lavas from Nicaragua (diamonds),
El Salvador (squares), and western Costa Rica (crosses) define binary
mixing arrays between carbonate-dominated and hemipelagic-dominated end
members. Sources include the carbonate (Carb) and hemipelagic (Hemi) sediment
sections on the Cocos Plate and three depleted sources, a depleted MORB
source and an E-MORB source from Sun and McDonough (1989) and an altered
oceanic crust (AOC) estimate. Any triangle, formed by mixing between the
two sediments and any of the three depleted sources, includes most but
not all the lavas. Fluid extracted from AOC and Hemi should have much
higher U/La and thus may expand the triangle over the observed range.
Regional variation in U/Th along the volcanic
front of the arc. This ratio is a useful tracer for sediment subduction
in Central America because of the unusually high U content and U/Th of
carbon-rich hemipelagic sediments near the top of the sediment section
on the Cocos plate, as found at DSDP site 495.
Map showing the distribution of earthquakes in Nicaragua and Costa Rica.
Seismic Reflection Data from Costa Rica/Nocargua available via the UTIG web site
UTIG has maintained this archive since 1975 with internal funding. Because many of the original investigations were publicly funded, the majority of these data are in the public domain. In 1998, The National Science Foundation provided funds for the media costs associated with our transcription from Exabyte to Digital Linear Tape (DLT). In order to make the data publicly available, and to preserve the integrity of the data over the long term, UTIG has created this database. Currently, there are approximately 23,000 files of data, of which 3000 of the files are stacked and processed data, and the remainder being shot gathers. The data is mostly in SEG-Y or SEG-D formats.
Last updated June 15, 2000