The following conversation is between Susan Russell-Robinson from the US Geological  Survey and Barbara Reynolds from USA Today . Q: Why , after 600 years of no activity , did Mount Pinatubo in Philippines erupt in 1991 ? A: Volcanoes  each have their own eruption styles . This volcano probably has a rule which makes it erupt in the order of every 500 to 1000 years , but a volcano in Hawaii seems to erupt every year , and some of the Alaskan volcanoes might erupt every 10 or 20 years . Q: So nothing caused it ? A: There's nothing out of the ordinary . If you were to take an ordinary calendar year , 50 to 75 or 80 volcanoes erupt around the world every year . There are 20 to 30 volcanoes every month that show signs of unrest . That might be a full-blown eruption or a whole host of activities like that . Q: What is "the ring of fire" ? A: If you look at where active volcanoes are placed around the world , there are somewhere between 500 and 600 of them . There is what appears to be almost a necklace that goes around the Pacific Ocean . It makes a ring where 60% of the world's volcanoes lie . Q: Why such a concentration there ? A: That's based on a theory that the oceans and the continents are like separate pieces . When continents and when that happens it seems to produce magma at depth and then you have volcanoes in the same ring . Which of the following can be considered as the best conclusion of the conversation?
There are so many volcanoes in the world and we are always in danger. Volcanoes have erupted more frequently than ever before. Volcanoes are waiting to be better known. Something must be done to protect the people near the ring of fire.