Pressure ridge (lava)
Encyclopedia
A pressure ridge is created in an active lava flow. Formation occurs when the outer edges and surfaces of the lava flow begin to harden. If the advancing lava underneath becomes restricted it may push up on the hardened crust, tilting it outward. Inflation also takes place and is a process where the plastic
layer of lava underneath expands as it cools and small crystals
form. The end result is a raised mound of hardened lava rock, usually a relatively narrow but long ridge. Tension cracks form on the surface of pressure ridges and run along the axis
of elongated ridges, and at both edges of broader ridges, sometimes referred to as pressure plateaus. Sometimes, along the edges of a pressure ridge, the tension crack can be large enough to create a liftup cave. Other caves can form inside pressure ridges in which conditions arose for the ridge to form and the lava inside subsequently drained leaving an inflationary cave
.
Plasticity (physics)
In physics and materials science, plasticity describes the deformation of a material undergoing non-reversible changes of shape in response to applied forces. For example, a solid piece of metal being bent or pounded into a new shape displays plasticity as permanent changes occur within the...
layer of lava underneath expands as it cools and small crystals
Crystal
A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...
form. The end result is a raised mound of hardened lava rock, usually a relatively narrow but long ridge. Tension cracks form on the surface of pressure ridges and run along the axis
Reflection symmetry
Reflection symmetry, reflectional symmetry, line symmetry, mirror symmetry, mirror-image symmetry, or bilateral symmetry is symmetry with respect to reflection. That is, a figure which does not change upon undergoing a reflection has reflectional symmetry.In 2D there is a line of symmetry, in 3D a...
of elongated ridges, and at both edges of broader ridges, sometimes referred to as pressure plateaus. Sometimes, along the edges of a pressure ridge, the tension crack can be large enough to create a liftup cave. Other caves can form inside pressure ridges in which conditions arose for the ridge to form and the lava inside subsequently drained leaving an inflationary cave
Lava cave
A lava cave is any cave formed in volcanic rock, although in typical usage it is reserved for caves formed by volcanic processes, which are more properly termed volcanic caves...
.