"North Korea's fourth test — in the context of repeated statements by U.S., Chinese, and South Korean leaders — throws down the gauntlet to the international community to go beyond paper resolutions and find a way to impose real costs on North Korea for pursuing this course of action," says Scott Snyder, a Korea expert at the Council on Foreign Relations. According to the NY Times, the test is bound to figure in the American presidential campaign, where several candidates have already cited the North's nuclear experimentation as evidence of American weakness — though they have not prescribed alternative strategies for choking off the program. The United States did not develop its first thermonuclear weapons — commonly known as hydrogen bombs — until 1952, seven years after the first and only use of nuclear weapons in wartime.
"When we see these fault systems producing multiple magnitude 4s, we start to get concerned that it could knock into higher magnitudes," says Daniel McNamara, author of a paper published online that a large earthquake near the storage hub "could seriously damage storage tanks and pipelines." "Given the number of magnitude 4s here, it's a high concern."
The last major earthquake in Los Angeles was the 6.7-magnitude Northridge quake, which killed close to 60 people in 1994. But it was not close to the catastrophe that seismologists predict if there is a major shift on the San Andreas fault, and the fact that it has not produced a major quake in recent years has fed a sense of complacency. Seismologists now say a 7.5-magnitude event on the Puente Hills would be "the quake from hell" because it runs right under downtown Los Angeles and have estimated that would kill up to 18,000 people, make several million homeless, and cause up to $250 billion in damage. "We want to keep the city up and running after the earthquake happens," says Lucy Jones aka "The Earthquake Lady," a seismologist with the United States Geological Survey and something of a celebrity in a city that is very aware of the potential danger of its location. "If everything in this report is enacted, I believe that L.A. will not just survive the next earthquake, but will be able to recover quickly."