The crater of the dormant volcano on Nisyros, the Dodecanese island’s main tourist attraction, has been declared off limits to visitors following recommendations by the Civil Protection Secretariat, in view of increasing temperatures and growing surface cracks in the area. «Systematic research has shown that earthquakes in 1995-96 triggered changes in the general condition of the volcano,» Evangelos Layios, director of Athens University’s geophysics laboratory, told Kathimerini. «For example, the hydrothermal system has increased in heat from 210 to 315 degrees Celsius, there is continuous microseismic activity as well as changes on the surface of the ground.» Layios said permanent seismologic networks should be set up in the area to monitor the volcano. A 139-meter crack in the ground on the volcano has almost tripled in length over the past year. This prompted the ban on visits to the crater.