sharon sanders
Editor-in-Chief & President
By Arthur C. Tarr,<sup>1</sup> Antonio Villase?or,<sup>2</sup> Kevin P. Furlong,<sup>3</sup> Susan Rhea,<sup>4</sup> and Harley M. Benz<sup>4</sup>
<sup>1</sup> U.S. Geological Survey, Emeritus, Box 25046, MS 966, DFC, Denver, CO 80225 USA
<sup>2</sup> Institute of Earth Sciences, CSIC, Lluis Sol? i Sabar?s s/n, 08028 Barcelona, Spain
<sup>3</sup> Department of Geosciences, Pennsylvania State University, State College, PA 16802 USA
<sup>4</sup> U.S. Geological Survey, Box 25046, MS 966, DFC, Denver, CO 80225 USA
http://pubs.usgs.gov/sim/3064/
<sup>1</sup> U.S. Geological Survey, Emeritus, Box 25046, MS 966, DFC, Denver, CO 80225 USA
<sup>2</sup> Institute of Earth Sciences, CSIC, Lluis Sol? i Sabar?s s/n, 08028 Barcelona, Spain
<sup>3</sup> Department of Geosciences, Pennsylvania State University, State College, PA 16802 USA
<sup>4</sup> U.S. Geological Survey, Box 25046, MS 966, DFC, Denver, CO 80225 USA
http://pubs.usgs.gov/sim/3064/