Can anyone explain me the scientific reason why 1977 earthquake was a catastrophe and the one at 1990 was "little"... Not so much difference, apparently. The same between 1940 and 1986... The papers I found on the internet are either too technical for me or consider that so clear that don´t explain further... Thanks!

"If you don't want a man unhappy politically, don't give him two sides to a question to worry him; give him one. Better yet, give him none." (Fahrenheit 451)