The most dangerous kind of volcano to live near is a

 Mount Vesuvius, it buried the cities of Pompeii and Herculaneum

That is the correct answer to the question, why is the southern portion of the ring of fire so complex?

Many foreign companies buy/build hotels in areas therefore most of the profit from tourism goes to these companies rather than the local economy or local people. 
also, these foreign companies might only employ foreign workers with experience meaning they receive more pay whereas local people would be employed for low skilled jobs and lower pay. 

thats all i can think hope it : )