May 27, 1997

William R. Lund, southern Utah regional geologist for the UGS, said the 1996 expedition to the Gobi-Altay region of southwestern Mongolia "provided a unique opportunity for me to work . . . in the world's premier laboratory for studying large surface faulting earthquakes." The UGS recently published Lund's report on the expedition. The publication, RI 233, is available for $2 in the Natural Resources Map & Bookstore, 1594 West North Temple.

The expedition was funded by the Nuclear Regulatory Commission, which is interested in earthquakes similar to the ones that struck near New Madrid, Missouri, in 1811 and 1812 and near Charleston, South Carolina, in 1886. Those quakes affected large areas of the mid-continent. In 1957, the Gobi-Altay, Mongolia, quake was one of the largest, with a magnitude of 8.3, and most complex to occur anywhere on earth this century. The rupture caused surface deformation in a zone 250 kilometers long and 40 kilometers wide, affecting the entire fault zone.

"Participation in the expedition allowed me to work with a variety of styles of active tectonic features that I had not previously encountered," Lund reported. "The insight gained by working with these kinds of structures . . . has broadened my perspective regarding paleoseismic analysis and will be of great value in future active-fault investigations in Utah. I was able to observe and learn from some of the world's finest paleoseimologists and other scientists. It was invigorating and challenging and reminded me of why I became a geologist in the first place, and why performing science in the public interest is so important."

The expedition members concluded that, while there are similarities between the Gobi-Altay fault zone and the San Andreas/Transverse ranges in California, the 1957 event is not a prototype for a major earthquake in southern California, as had been speculated. However, the 1957 quake and other Gobi-Altay events this century "are more characteristic of the New Madrid earthquakes, involving complex rupture sequences (minutes to weeks apart) in intraplate settings where stress release is accommodated by multiple faults in a large volume of crust."