When following the ground motion selection guide, the values resulting from one step are then used as inputs in the next step. Should we be using the values that are shown in the selection guide as inputs in the next step, or the values we get from the various websites? I ask because these are for some reason different. For example, the USGS disaggregation tool, when given the exact parameters shown in the selection guide, produces different results (i.e. distance = 66.85 km, not 50.33 km). Then, when searching through NGA-West2, the selection guide suggests to filter the distance to 50.33 km +/- 20 km = [30.33,70.33] km. Restating the question, should we use this value, or 66.85 km +/- 20 km = [46.85,86.85] km? Thank you!

Question

When following the ground motion selection guide, the values resulting from one step are then used as inputs in the next step. Should we be using the values that are shown in the selection guide as inputs in the next step, or the values we get from the various websites? I ask because these are for some reason different. For example, the USGS disaggregation tool, when given the exact  parameters shown in the selection guide, produces different results (i.e. distance = 66.85 km, not 50.33 km). Then, when searching through NGA-West2, the selection guide suggests to filter the distance to 50.33 km +/- 20 km = [30.33,70.33] km. Restating the question, should we use this value, or 66.85 km +/- 20 km = [46.85,86.85] km? Thank you!

Accepted Answer

The ground motion selection guide is provided as reference. Please use the values from the platform for your own selection. If you have trouble finding a suitable ground motion set with these new values, then use the values from the guide and state the reasons why you did not use the exact values.