IsoBal Tutorial

AN ISOBAL TUTORIAL This handout, first prepared by Katherine Giles of New Mexico State University, will familiarize you with the program ISOBAL which calculates Airy isostasy for two columns. To run ISOBAL, follow the directions at the top of the first problem set. What you type is shown in bold italic type. Once you are in ISOBAL, you will see this screen: At the top of the screen are four commands: D_epth, L_eft, R_ight, and Q_uit. They can be implemented by typing the first letter of the command. Watch this line – the available commands change depending on where you are in the process. Type: d (not case sensitive) This command allows you to change the compensation depth, in other words, the depth (in km) to which calculations will be made. The default value is 100 km. Type: 100 Enter Keep a compensation depth of 100 km for now. Type: L L_eft refers to the reference column, which will be displayed on the left of the screen. This column defines your concept of “ordinary” lithosphere. The column of interest (the active column which is displayed on the right) will be balanced against this standard column. Isobal Tutorial Geos 440/540 Page 2 of 5 Type: S By choosing S_tandard, you have chosen a standard column with the following structure: 0-10 km rho=2670 kg*m-3 10-20 2870 20-30 2950 3300 On -the screen, z = depth of the layer, t = thickness of the layer and rho = density of the. layer. Notice that depths ...