Figure 2
From: The Guanacaste Volcanic Arc Sliver of Northwestern Costa Rica
Seismotectonic setting. Geographic reference system here and in Fig. 3 is that found on most topographic maps of Costa Rica, the Ocotepeque 1935/Costa Rica Sur. Latitude and longitude graticules using the WGS 84 reference frame also shown here and in Fig. 3. Digital elevation model and shaded relief map derived from enhanced Shuttle Radar Topography Mission (SRTM) data with an effective resolution of 30 m. Lighting from 020°. Lower-case bold letter g. with view direction for photograph at Fig. 4g. The stereonet shows poles to faults at the outcrop at location g. The red poles show the geometry of the bounding strike-slip fault, the principal displacement zone27 at the eastern end of the exposure (right end of white symbol), whereas the black poles show normal faults that record dip separations that average ~0.6 m. The circled black pole is the westernmost fault. Portions of the Cote-Arenal fault and Chiripa faults from Fig. 3 are included as a dotted line. The dashed line outlines the aftershock area for the 13 April 1973 Ms6.5 Tilarán earthquake29. The dashed magenta boxes show the locations of the two inset seismicity profiles in which the uncertainty in the earthquake locations is shown by vertical and horizontal red lines. Towns are shown with a dot-plus symbol. Town abbreviations: BI = Bijagua and U = Upala. Volcanoes: M = Miravalles and T = Tenorio. SgD with red arrow = Sangregado Dam. Map generated using QGIS version 2.14 with SRTM 1 Arc-Second Void Filled digital elevation data courtesy of the U.S. Geological Survey from https://earthexplorer.usgs.gov/. Keys, labels and symbols were added using Adobe Illustrator CC 2015 release.
