Continuous positive airway pressure (CPAP) machines are used to maintain an open airway in patients diagnosed with obstructive sleep apnea. The machine functions by blowing pressurized air into the airway via mask at a setting determined by sleep study and prescribed by a physician.
Also the second largest impact structure on Earth, the 1.85 billion years old Sudbury crater in Canada, hosts world-class mineral deposits - in this case nickel-rich minerals that were melted and concentrated by the extreme heating caused by the impact.
But not all volcano craters are found at the top of the volcano. They can also appear on the flanks of large volcanoes, when side vents reach the surface and erupt. These are known as flank craters, while the crater on top is called a summit crater. volcano crater is a circular depression around a volcanic vent. This is where the lava, ash and rock erupt out of a volcano. In most situations, the volcano crater is located at the top of the volcano. Volcano Crater.