The award for the most dangerous fault line has to be made with some special considerations: is the fault line near or running through an urban area or a nuclear facility? Are there other natural formations, such as volcanoes and oceans, that would lead to eruptions or tsunamis? Is the human and financial toll the major consideration? Is the decision made based on the frequency or quakes or on the likliehood of quakes that are stronger then 7.0 on the Richter Scale?
Major considerations also include whether the structures and infrastructures of the area are built to withstand major quakes and whether the quakes might be of lesser scale, but more frequency.
The recent earthquakes in Haiti and Chile were devastating in terms of human and economic consequences, but if a major quake occurred in a mostly uninhabited area, would the consequences be so dire and would the quake be considered as dangerous?
There are no universal answers about the single most dangerous fault line, but there are several that are considered to be the most dangerous.
Considering the human toll in urban areas and the potential for devastation to human life and whole economies, the most dangerous fault in the United States is the Hayward Fault, which runs through the East Bay of the San Francisco, California megolopolis. This fault notoriously runs through the stadium at the University Of California at Berkeley. It is the only “most dangerous” fault that does not involve direct contact between tectonic plates, but is well within the fracture zones of the American Plate and the Pacific Plate.
Ominously, an earthquake of 6.8 magnitude or greater occurs about every 140 years on the Hayward fault, and the last one was 140 years ago. Estimates are that the situations of over 5 million people and over 150 billion in physical damage would be the immediate impact, with about 1.5 trillion in the extended impact over the surrounding counties and areas. Considering that Oakland and San Francisco are the major cultural, educational, financial, transportation and business centers of the North State, the impact would be felt throughout the West Coast.
The San Andreas Fault line in Southern California is often considered to be the most dangerous, considering that it is at the edge of the Pacific and American tectonic plates, with a bit of the Juan De Fuca Plate thrown in.
The San Andreas fault line runs through both a Southern and Northern megolopolis where the human and physical property tolls would be vast. The San Andreas fault is also one of the longer fault lines, at well over 1000 miles long, and major corrections in many spots are considered to be overdue.
The North Anatolian fault in Turkey is another long fault line that, along with others, cover most of the nation. This fault line has high earthquake activity where quakes in excess of 7 on the Richter scale are likely. The North Anatolian fault is another tectonic boundary that is between the Anatolian plate and the Karniliovia Junction.
The Mocha and Valdivia fracture zone is a fracture that extends from the Nazca tectonic plate, which butts up against the South American Plate. This fault extends from the Mocha Island off of Chile and south to Peru. Recent and not so recent activity in Chile and Peru, combined with high populations and possibly less attention to seismic accommodations in many places along the zone make this fault one of, if not the most dangerous fault.
The Pacific Rim is host to many of the normal quakes, which are of 6.9 magnitude or less, and which appear to occur in the world about every 2 1/2 days. Except for California, no “most dangerous” faults are mentioned for the Pacific Rim.
USGS, “Hayward Fault”
BBC, UK, “Earthquake Storms”
Wikipedia, “North Anatolian Fault”
The World’s Tectonic Plates
