To increase the amount of virtual memory go to Control Panel > System > Advanced > Performance > Settings > Advanced > Virtual Memory Change > Custom Size > adjust as needed. 2 times your physical RAM is a good minimum and 3 times your physical memory in MB is good for your maximum.
The three different types of lava differ in composition and flow rate. Rhyolitic lava is the slowest moving type of lava, since it has a high viscosity due to a high silica concentration. Basaltic lava is the fastest moving lava because of its low viscosity resulting from a low silica content.
Scientists recognize four main types of volcanoes: stratovolcanoes, shield volcanoes, cinder cones, and ashflow calderas. Stratovolcanoes, or composite volcanoes, get their name from the different layers, or strata, of ash and lava that form them.