New Zealand geologists have begun work on a major international study of a rare exposed active continental fault in the southwest Pacific nation of Papua New Guinea.
The geologists from Victoria University have carried out reconnaissance fieldwork on the remote Maiu'iu Fault in the Owen Stanley Mountains in preparation for an expedition of scientists from New Zealand, the United Kingdom and the United States.
Professor Tim Little and Dr Kevin Norton of the university would lead the team, which hopes to get insights into the mechanics of large faults in active continental rifts by measuring how rapidly a single large fault can move, to determine whether such slips can accumulate slowly and steadily without earthquakes, and to analyze the amount of friction in the fault.
The Maiu'iu Fault was unique in that it was moving extremely quickly and was inclined on a very low angle, Little said in a statement Monday.
"The rapid slip leads to the uplift and exposure of a smooth fault surface, which can be studied in great detail in the field. More than a 25-km width of the uplifted fault surface is currently visible in the landscape, rising from near sea level at the base of the scarp to an elevation of greater than 2,800 meters near the crest of the mountains," he said.
"The average rate of tectonic slip on this fault is very high, perhaps 1 centimeter a year, which is the fastest rate for a fault of its kind in the world. It's being pulled up so rapidly that erosion isn't able to keep pace, which means a smooth expanse of the fault surface is preserved in the landscape.
Norton said the speed of the fault's movement would be analyzed using cosmogenic dating, a technology that could accurately determine the ages of landforms.
"When the radiation hits rock it turns some of the atoms into new different elements called cosmogenic nuclides. The longer a rock sits at the surface, the more these nuclides accumulate," Norton said in the statement.
The research team planned to begin detailed investigation of the fault by the middle of next year.