Regelation is the occurrence in which ice melts to water below 0°C when pressure is applied and then refreezes back to ice when pressure is removed.
Regelation exhibits the concept of compressing ice and changing it into water under pressure, which then solidifies when the pressure is removed.
Final answer:
Hence, the occurrence in which ice melts to water below 0°C when pressure is applied and then refreezes back to ice when pressure is removed is known as regelation.