ژئومورفولوژی

جغرافیای طبیعی

ژئومورفولوژی

جغرافیای طبیعی

Geomorphology from Space

Geomorphology from Space


During the mid-1980s, the writer began research on space imagery for producing small-scale geomorphic maps and for investigating some specific geologic problems involving interrelations of landforms and tectonic processes. Aware of this, the Geology Discipline Leader at NASA Headquarters saw the potential benefits and decided to fund a conference on Regional Geomorphology. The writer got to organize it. Thus, on January 14-16, 1985, we held a Workshop on Global Mega-Geomorphology at Oracle, Arizona. Thirty international participants spent the first two days presenting papers and engaging in lively discussions and then met in four working groups on the third day to consider the role of space imagery in these thematic frameworks: 1) Global Geomorphology, 2) Evolution and Inheritance of Landforms, 3) Process Thresholds, and 4) Planetary Perspectives. This workshop (summarized in NASA Conference Publication 2312) laid a foundation for future research in a field whose name– Global Mega-Geomorphology, first proposed as a new concept in 1982–was certified by the attendees.

There was an almost immediate payoff. The writer received NASA funding to prepare a publication that focused on using space images to characterize landforms. Joined by Robert Blair, Jr of Fort Lewis College, Durango, CO, as co-editor, we assembled fourteen scientists (including ourselves) to write twelve chapters, each covering a different geomorphic theme, in a 717 page book entitled: Geomorphology from Space: A Global Overview of Regional Landforms (NASA SP-486), which appeared at the end of 1986. Although we distributed 4,000 copies, the book did not, at first, receive adequate publicity. In recent years, authorities have acknowledged it as an invaluable compendium of geomorphic information, as well as a comprehensive survey of the world's geology, and it has led to renewed interest in regional analysis.

Unfortunately, there was no second printing, so NASA and the U.S. Government Printing Office (GPO) cannot fill requests for copies. But, NASA leaders recognized its value, so people in the educational program at the Jet Propulsion Laboratory (JPL) decided to add it to their growing set of CD-ROMs, available at low cost to professionals and the public. The staff at NASA's Goddard Space Flight Center did much of the scanning and layout, so this reproduction of NASA SP-486 with a new format now is available from JPL, with a limited quantity of CD-ROMs free to educators. A version of the book is also accessible on the Web at: http://daac.gsfc.nasa.gov/DAAC_DOCS/geomorphology/GEO_HOME_PAGE.html

One of the serendipitous outcomes of this book is that Dr. Robert S. Hayden was persuaded to prepare several geomorphic maps from full and partial Landsat images, as a demonstration of the possibilities of mapping at this scale from space imagery. We reproduce here a Landsat-2 image of the upper Gulf of California (mostly in Mexico) and the beginning of Baja California. Below it is his geomorphic map, with key

map: