Residents in a Mexican town are on edge as fears grow that a new volcano is brewing beneath their feet. Despite assurances from experts that a new volcano is not likely to form, a July 9 eruption of gas and smoke from a field, coupled with cracks on the ground in Pueblo Viejo, in the southern state of Michoacan, has left residents fearing the worst, according to Reuters. Temperatures of nearly 500 degrees Fahrenheit reportedly have been registered in the subsoil. To protect curious residents, local officials have cordoned off the area. Experts say they do not believe the activity is the birth of a new volcano, at least at this point. "We cannot say that this is the birth of a volcano because until now there has been no earth movement in the area, which tells us it can almost be ruled out," Pedro Carlos Mandujano, the state Civil Protection coordinator, told Mexico News Daily. A preliminary investigation has determined that the geothermal activity that produced the eruption comes from an underground swamp. Experts added that they believe the heat is being generated by the composting of organic material. Mexico is part of the Pacific ring of fire and home to some 3,000 volcanoes, 42 of which are considered active. The most active volcanoes are Popocatepetl, Colima and El Chichon, which had a major eruption in 1982. The eruption was so massive that cooled the world's climate the following year, according to Volcano Discovery.