Risk-Targeted-Ground-Motion-Calculator-Documentation.md

+# Sample input
 
+Application input can be user-provided or drawn from the [USGS Hazard Curve Data files](http://earthquake.usgs.gov/hazards/products/). The following example incorporates the “Hazard Curve Data” file for “5Hz (0.2 Second)”; specifically the data for the coordinates (34.05, -118.25) in Los Angeles are used:
+
+Spectral Response Acceleration Values (corresponding to the x-axis on a hazard curve):
+0.005, 0.0075, 0.0113, 0.0169, 0.0253, 0.038, 0.057, 0.0854, 0.128, 0.192, 0.288, 0.432, 0.649, 0.973, 1.46, 2.190, 3.28, 4.92, 7.38
+
+Annual Frequency of Exceedance Values (corresponding to the y-axis on a hazard curve):
+0.5855, 0.5208, 0.4389, 0.3515, 0.2679, 0.1953, 0.1376, 0.09335, 0.06027, 0.03659, 0.02096, 0.01146, 0.005985, 0.002934, 0.001287, 0.0004781, 0.0001411, 0.00003023, 0.000003828
+
+
+# Sample output
+
+Output summary (yellow box)
+This section provides the risk-targeted ground motion (RTGM) corresponding to a 1% probability of collapse in 50 years. The uniform hazard ground motion (UHGM) used as a starting point for the calculations is provided, as is the Risk Coefficient (RC) representing the ratio of RTGM to UHGM for the site of interest.
+
+
+Five plots illustrating the step-by-step process of calculating the risk-targeted ground motion are briefly discussed below.
+
+Hazard Curve
+This is simply a graphical representation of the Spectral Response Acceleration Values (x-axis) and Annual Frequency of Exceedance Values (y-axis) provided by the user. For more information on these values, users are referred to the Documentation for the 2008 Update of the United States National Seismic Hazard Maps (embedded link: http://pubs.usgs.gov/of/2008/1128/).
+
+Fragility Curves
+These are generic fragility curves…
+
+Derivative of Fragility Curves 
+These are simply the derivatives of each respective fragility curve. Provided as a reference for the next step in the calculation process.
+
+Hazard Curve x Derivative of Fragility Curves
+Combining the hazard curve for the site with each fragility curve produces a curve illustrating the annual collapse frequency density of a generic structure at the site of interest. Provided as a reference for the next step in the calculation process.
+
+Cumulative Integral of Hazard Curve x Derivative of Fragility Curves
+Integrating the Hazard Curve x Derivatives of Fragility Curves produces the cumulative 50-year collapse probability of a generic structure at the site of interest. 
+
+
+API Documentation
+This section describes… (then proceed with the currently provided documentation)