In the 1950s, the behavior of volcanoes could be simulated with analog circuits.

I haven't been able to find a diagram of these circuits, however I'm curious as to what the electrical components might have represented:

• Variable DC Voltage = Pressure at the magma reservoir
• Resistance = Viscosity and opposition to magma/lava flow to the earth's surface.
• Capacitance = Pressure of magma/lava column at the earth's surface.
• Diode Threshold Conduction = magma/lava melting threshold for a given pressure below the earth's surface.

To help figure out the circuit, here's a little fact about how volcanoes actually form.

The "mantel" (the region 3 layers below the crust) is actually a "plastic solid" which suddenly melts (and creates magma/lava) when the pressure is removed by geologic processes such as plate tectonics. However as the magma/lava rises in the column (forming the volcanic vent), the pressure on the mantel increases. Eventually, the pressure increases to a threshold at which the melting stops and this would represent a dormant volcano.

To electrically simulate the process, I suppose the mantle could be the DC source connected to the diodes. When DC is applied to the string, the diodes initially conduct (-IE- the mantle melts) until the capacitor charges enough to created a back EMF (the increase in pressure in the magma/lava column) and the conduction (melting) eventually stops.

I suppose an eruption could also be simulated by discharging the capacitor so the diodes conduct all the time which is analogous to continuous melting and lava flowing to the surface.

 

Someone must have the sim info; there's an app for it!

 

I'm quite aware that modern simulators use computational fluid dynamics (CFD) and computer graphics to display just about any phenomenon.

However, I'm more curious about how an analog simulator would work. These specially designed simulators were used in the 1950s and 60s for modeling rivers, weather, volcanoes, etc. In the 70's, I saw one for modeling the flow of the Mississippi River.

 

Here you go:

 

.... and here's a simpler version:

 

I'm quite aware that modern simulators use computational fluid dynamics (CFD) and computer graphics to display just about any phenomenon.

However, I'm more curious about how an analog simulator would work. These specially designed simulators were used in the 1950s and 60s for modeling rivers, weather, volcanoes, etc. In the 70's, I saw one for modeling the flow of the Mississippi River.

I once saw a simulator for air flow in mine tunnels. I don't know if there is any commonality with what you are thinking of.

The unit I saw had a _bunch_ of analog modules. Each module was set to represent (a few?) parameters of a section of tunnel. I don't know if this unit was a custom or standard product. I do know that it was old. It was in a mining history museum.