Show VOLCANOES ARE ALWAYS THREAT St again gives islanders a bad scare home Strom St boll the constantly active volcano on a small island in the die mediterranean at the toe of italy burst into more than usual activity a i few days ago causing fear among the residents of the island and the nearby ina luland the activity quickly subsided to normal relieving the terrors of the inhabitants vho aho kr know that italis volcanoes volcano ps have a record for heing bad actors when aroused vesuvius in 71 70 11 C Q burled buried pompeii and two other cities and after more than l aioo jears relative inactivity burst forth with ith tremendous violence in and aped out people the conditions which mitch exist in the neighborhood od of these well known yo vol canoes are duplicated in hundreds of places throughout the world where here volcanoes tire are located in areas so highly developed and densely not all volcanoes have cones coes there are probably several thousand active or semi active volcanoes on 1 the earth but only about are 1 known anil and recorded to the average person a volcano Is a cotie cone shaped montain out of the lie peak of which issue sue fire steam hot gases and molten rode rock to the scientists who specialize in the lie study of this Is but one of the many phases of volcanic activity to them the cone shaped mountain Is common only to certain types of volcanoes the cone Is something th eliat Is built up by the he volcano and some volcanoes do not build cones NUi whether ether or not a volcano builds a cone depends on the type of rocks associated with it blauna itauna loa in ili hawaii ilaw all covered a vast plain etli with its flow before building its present crater the italian volcanoes canoes salso also ha have econe cones of com comparative paralle recent origin Strom bolls cone cone has been built up within 2000 years it i started out RS as did etna and Vesti vesuvius vius as an tinder water volcano the higher a volcano builds its cone the harder it Is for the lava to reach the vent and then vents rents are developed at lower levels chain around the earth great chains of volcanoes stretch I 1 around the earth the greatest chain Is in the mountain range that extends like a ring around die alie pacific ocean other chains stretch across asia and europe Kii rope the volcanic islands of the pacific from hawaii through the philippines to new zealand mark sub oceanic volcanic areas what causes volcanoes to erupt Is not known in recent decades observatories have been established to study them and much information Is being gathered their activity Is due to internal heat of the earth this heat beat la Is not the heat of the great internal core of the earth because that heat is reached only at great depths and volcanoes do not have their roots at greater depths than six to fifteen miles the heat which causes volcanic activity Is believed to be due to chemical action and to the great pressure produced by occluded and chemically produced gases as react reactions ioni take place between rock substances i some forces of worldwide world wide effectiveness also may be involved this th a Is indicated by the frequent simultaneous I 1 activity of volcanoes or of earth quakes in widely separated parts of the world |