Strata sheet

Click now the “Strata” sheet in order to see a screen similar to the one shown in Fig. below. The “Strata” sheet is subdivided in three parts. The first part close to the title is labeled “Strata in Catalog”.

The layer parameters

The second part of the “Strata” sheet is devoted for editing the layer parameters. First note the text box “Strata Name” which reports the name of the layer model you are actually working on. It will be the same as the one indicated above in the textbox “Name” if you accessed a layer model from the catalog. You must change the name in “Strata Name” if you wish to create a new entry in the catalog. Use the button “Save in Catalog” to the right to save the new layer parameters to the catalog. Of course, if SHAKYGROUND finds an already existing layer model in the catalog which has the same name as indicated in the box “Strata Name” you’ll be asked whether to overwrite the layer model in the catalog.
Below the textbox “Strata Name” you find on the left hand side of the sheet a column of text boxes related to the single layers of the layer model. The first reports the layer name, the subsequent ones the various geotechnical parameters, i. e., the thickness of the layers, their shear wave velocity, their density and the quality factor Q. Similar to the “Source” sheet the geotechnical parameters reported in the textbox on the right hand side of the layer sheet represent average values. These average values can be subjected to a random fluctuation, whose bandwidth in % is specified with a column of spinboxes. The definition of the bandwidth of the random fluctuation is the same as the one applied to the source parameters. For example, if the random fluctuation of a layer thickness of 300 m has been selected as 10%, then this parameter will be varied in each simulation with a standard deviation of 30 m, that is ± 10% or a bandwidth of 20 %. The 3rd column of boxes on the right hand side report the bandwidth of the random parameter variation in absolute values. Note that these boxes cannot be used for changing the bandwidth of random parameter variation.
In the lowermost part you find a box which reports all layernames of the layer model together with their geotechnical parameters and the corresponding bandwidth of random variation. Additionally the layers are assigned with colors. This box, lets call it “Overall Box”, contains all information about the layer model and must be accessed if you want to edit the parameters of a layer. The “Overall Box” is rather large, so that you may not see it entirely on your screen. Use the horizontal arrow at its base in order to scroll it. Now click the color or the name of the layer you want to access. SHAKYGROUND reports the parameters of this layer in the central part of the sheet, i. e. in the textboxes related to name and parameters of the single layer and the subsequent columns of boxes reporting the random parameter variation. Use these boxes to make your changes. You now have two options to make your changes active in the layer model. For this purpose use the buttons on the left hand side in the lowermost part of the layer sheet. Clicking the “Next” button will append a layer with your new parameter set at the base of the layer stack. With “Insert” this layer will be copied above the previously selected layer. Finally, if desired, select once more the layer you edited and press the “Delete” button. If you don’t do so you simply augment your layer stack.
The creation of new layers and layer models can be performed in a straight forward manner, just using the tools described. First specify a new name in the “Strata Name” Box. If you don’t like the model which you may find in the “Overall Box” click the layers there and delete them one by one, until your “Overall Box” is empty. Now specify the layer name in the “Layer name” box and enter the parameters in the subsequent boxes. Use the spinboxes if you wish to vary your layer parameters randomly. Then “Insert” the layer. Repeat this procedure for every desired layer. Recall that for insertion of the layer in the layer stack you have two possibilities, i. e., to insert it above the previous one with the “Insert” button or to append it at the base of the layer stack with “Next”button. Be aware of the fact that what finally counts for the simulation are the contents of the “Overall” box. Your insertion of layer parameters is completed when you have clicked either the “Insert” or the “Next” button.
The “Up” and “Down” buttons above the “Next” button represent an additional tool for the manipulation of layer models. Click a layer in the “Overall Box” then click the “Up” or “Down” button. SHAKYGROUND interchanges the position of the selected layer with the upper or lower neighboring one according to the button you have selected. This action becomes available if there already a layer model of at least two layers.