How can stop lava?

Answer 1

Different methods have been used including: breaching the sides of a lava tube or channel, diverting the flow, constructing barriers, and bombing the lava flow. Another way to stop a lava flow is to increase the lava flow's viscosity by spraying it with water, increasing the rate at which gas escapes from the flow, stirring the flow, or seeding the flow with foreign nuclei .
In Italy, engineers have installed retaining walls to try and slow down lava flows coming down the side of Mount Etna, on the island of Sicily. These walls did slow down the lava flows enough that they didn't reach inhabited land. In Hawaii, engineers bombed narrow lava tubes, forcing the lava to lose energy. And in Iceland, firefighters sprayed water on lava flows for nearly 5 months, cooling it so that it solidified early and didn't block an important port.