NOTICE: The project that is the subject of this report was approved by the Governing Board of the
National Research Council, whose members are drawn from the councils of the National Academy
of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of
the committee responsible for the report were chosen for their special competences and with regard
for appropriate balance.
This study was supported by Grant No. EAR-9809585 between the National Academy of Sciences
and the National Science Foundation. Any opinions, findings, conclusions, or recommendations
expressed in this publication are those of the author(s) and do not necessarily reflect the view of the
National Science Foundation.
International Standard Book Number 0-309-07133-X
Library of Congress Card Number 00-111596
Additional copies of this report are available from: National Academy Press 2101 Constitution
Ave., NW Box 285 Washington, DC 20055 800-624-6242 202-334-3313 (in the Washington
Metropolitan Area) http://www.nap.edu
Cover: Spatial scales relevant to Earth science processes. Lower middle: scanning electron photomicrograph of Streptomyces sp. growing on a polished hornblende surface, showing 400 to 600 nmwide hyphae. SOURCE: H. Buss, Pennsylvania State University. Bottom: mid-crustal exposure of
an early Paleozoic subduction zone in northwestern Norway. SOURCE: L. Royden, Massachusetts
Institute of Technology. Top left: synthetic aperture radar image showing the postseismic displacement (10 mm interval) of the 1999 Hector Mine earthquake, California. SOURCE: data from the
European Space Agency Satellite ERS-2 were acquired and processed by D. Sandwell, L. Sichoix,
A. Jacobs, R. Scharroo, B. Minster, Y. Bock, P. Jameson, E. Price, and H. Zebker, Scripps Institution of Oceanography. Upper middle: images of mountains and calderas on Jupiter’s volcanic moon
Io taken by NASA’s Galileo spacecraft. SOURCE: Jet Propulsion Laboratory.
Copyright 2001 by the National Academy of Sciences . All rights reserved.
Printed in the United States of America
ii
About this PDF file: This new digital representation of the
original work has been recomposed from XML files created
from the original paper book, not from the original
typesetting files. Page breaks are true to the original; line lengths,
word breaks, heading styles, and other typesetting-specific
formatting, however, cannot be retained,
and some typographic errors may have been accidentally inserted.
Please use the print version of this publication as the authoritative
version for attribution.
National Research Council, whose members are drawn from the councils of the National Academy
of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of
the committee responsible for the report were chosen for their special competences and with regard
for appropriate balance.
This study was supported by Grant No. EAR-9809585 between the National Academy of Sciences
and the National Science Foundation. Any opinions, findings, conclusions, or recommendations
expressed in this publication are those of the author(s) and do not necessarily reflect the view of the
National Science Foundation.
International Standard Book Number 0-309-07133-X
Library of Congress Card Number 00-111596
Additional copies of this report are available from: National Academy Press 2101 Constitution
Ave., NW Box 285 Washington, DC 20055 800-624-6242 202-334-3313 (in the Washington
Metropolitan Area) http://www.nap.edu
Cover: Spatial scales relevant to Earth science processes. Lower middle: scanning electron photomicrograph of Streptomyces sp. growing on a polished hornblende surface, showing 400 to 600 nmwide hyphae. SOURCE: H. Buss, Pennsylvania State University. Bottom: mid-crustal exposure of
an early Paleozoic subduction zone in northwestern Norway. SOURCE: L. Royden, Massachusetts
Institute of Technology. Top left: synthetic aperture radar image showing the postseismic displacement (10 mm interval) of the 1999 Hector Mine earthquake, California. SOURCE: data from the
European Space Agency Satellite ERS-2 were acquired and processed by D. Sandwell, L. Sichoix,
A. Jacobs, R. Scharroo, B. Minster, Y. Bock, P. Jameson, E. Price, and H. Zebker, Scripps Institution of Oceanography. Upper middle: images of mountains and calderas on Jupiter’s volcanic moon
Io taken by NASA’s Galileo spacecraft. SOURCE: Jet Propulsion Laboratory.
Copyright 2001 by the National Academy of Sciences . All rights reserved.
Printed in the United States of America
ii
About this PDF file: This new digital representation of the
original work has been recomposed from XML files created
from the original paper book, not from the original
typesetting files. Page breaks are true to the original; line lengths,
word breaks, heading styles, and other typesetting-specific
formatting, however, cannot be retained,
and some typographic errors may have been accidentally inserted.
Please use the print version of this publication as the authoritative
version for attribution.