Most volcanoes form near colliding plate boundaries.
- Lava flows out of a volcano through a hole called a vent.
- The top of the main vent of a volcano is also called a crater.
- If a volcano produces only layers of lava, the volcano will have gently-sloped sides.
- Volcanoes with steep sides have made some or all of their layers with ash and rocks.
- If a volcano is not active, its crater can sometimes fill with rainwater to form a lake.
- Stay away from active volcanoes.
- If you live near an active volcano, keep goggles and a mask in an emergency kit, along with a flashlight and a working, battery-operated radio.
- Know your evacuation route. Keep gas in your car.
If a Volcano Erupts in Your Area
- Evacuate only as recommended by authorities to stay clear of lava, mud flows, and flying rocks and debris.
- Avoid river areas and low-lying regions.
- Before you leave the house, change into long-sleeved shirts and long pants and use goggles or eyeglasses, not contacts. Wear an emergency mask or hold a damp cloth over your face.
- If you are not evacuating, close windows and doors and block chimneys and other vents, to prevent ash from coming into the house.
- Be aware that ash may put excess weight on your roof and need to be swept away. Wear protection during cleanups.
- Ash can damage engines and metal parts, so avoid driving. If you must drive, stay below 35 miles (56 kilometers) an hour.