Presidential Address:

Keith A. Howard, U.S. Geological Survey

How Calderas Work—Perspectives from the Galapagos and Yucca Flat

  • DINNER MEETING - Tuesday, June 2, 2009
  • Location: Stanford University

  • 5:30 PM-Social (3/4) Hour: . . . Hartley
  • 6:15 PM-Dinner: . . . Hartley
  • 7:30 PM-Meeting: . . . GeoCorner Room 320-105

    see Map showing GeoCorner

    Anyone wishing to attend the lecture only is welcome at no cost.

    This will be the 407th meeting since 1954


    Active calderas in the Galapagos Islands illustrate four processes that apply widely to calderas: cyclic floor collapse and refilling, long-runout wall avalanching, syn-collapse water-driven eruption triggered by magma withdrawal, and a floor-collapse mechanism. Collapsed caldera-floor structures mimic sandbox caldera models and pits that subsided over underground nuclear tests, in which identifiable structural zones imply an inner ring of reverse faults smaller in diameter than the evacuated chamber, and an outer ring of normal faults wider than the chamber. This suggests a broadly applicable method of estimating chamber diameters.

    About the Speaker

    photo of Keith
    Keith Howard

    Keith Howard is an emeritus research geologist with the USGS in Menlo Park, Calif. His interests include tectonics, granites, river geomorphology, planets, and volcanoes. He conceived and initiated the USGS program on climate change in the 1970s. He holds BS and MS degrees in geological engineering from U.C. Berkeley, a Ph.D. in geology from Yale, and was a Fulbright senior scholar at Cambridge.

    Reservations: The preferred way to make reservations is simply to email John Spritzer at by May 29, tell him you will attend, commit to pay, and bring your payment to the meeting. John always emails a confirmation; if you don’t get one, assume email crashed yet again and email him a second time. A check made to “PGS” is preferred, payable at the meeting.

    If you want to pay in advance:

    Everyone (including Stanford folks now) Please make dinner reservations by May 29. Contact John Spritzer, at U.S. Geological Survey, 345 Middlefield Road, MS-973 Menlo Park, CA 94025, Tel.: (650) 329-4833. Send check made out to “PGS” to John.

    Note: the prices have gone up a little.

    Dinner is $35.00. Includes wine (5:30 to 6:15 PM.) and dinner (6:15-7:30 PM.).

    For students from all universities and colleges, the dinner, including the social 3/4-hour, is $8.00 and is partially subsidized thanks to the School of Earth Sciences, Stanford University (Note, no-show reservations owe the full price).

    Doris, whose wonderful crew prepares our meals, asked that we let you know that people who are late RSVPing and people who show up without a reservation will be welcome but that they will be eating on paper plates with plastic utensils (food supply permitting).

    Dues for Academic Year 2008-2009 ($10.00) should be sent to John Spritzer, U.S. Geological Survey, 345 Middlefield Road, MS-973 _Menlo Park, CA 94025. John’s phone: (650) 329-4833.

    Officers: Keith Howard, President; Vicki Langenheim, Vice President; Mike Diggles, Secretary; John Spritzer, Treasurer; Elizabeth Miller, PGS Stanford University Coordinator

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    Date created: May 27, 2009
    Last modified: 9/20/2009
    Created by: Mike Diggles, Webmaster-Secretary, PGS.

    c/o U.S. Geological Survey, MS-951, 345 Middlefield Road, Menlo Park, CA 94025. (650) 329-5404. email Mike Diggles at

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