The best protection against volcanic destruction is to stay far away.
That may be impossible, since volcanoes can appear almost anywhere, but it isn’t likely one will pop up in your backyard as one did in Paricutin, Mexico.
There are, however, some ways to try and reduce the inevitable damage from volcanic eruptions. Channels can be built to direct the flow of lava away from populated areas. Levees, dams, and dikes can be erected to contain the flow of lava and mud.
Artificial earthworks, such as mounds, can provide high ground for refugees. Water is sometimes poured extensively over lava flows to encourage solidification.
The U.S. Air Force has bombed lava flows in Hawaii with some success in preventing rampant destruction.