The Mid-Atlantic ridge is the division between the American and European tectonic plates. The ridge runs across Iceland and forms an active volcanic belt, stretching from the south-west to the north-east corner. Within the active volcanic belt a number of high-temperature geothermal fields are found. These are areas with water temperature over 200°C at 1000 meters depth. About 32 high temperature fields have been identified in Iceland. Outside the active volcanic belt, 250 of 'low temperature fields' are found. These are defined as areas with temperatures less than 150°C at 1000 meters depth. The closer the low temperature fields are to the active volcanic belt, the higher the temperature.