Recent Changes in Geyser Activity at Loburu, Lake Bogoria, Kenya Rift Valley

 By Robin W. Renaut, R. Bernhart Owen, and John K. Ego

 Abstract:  Major changes in hydrothermal activity have accompanied frequent fluctuations in the level of Lake Bogoria, Kenya, during the past decade.  Even minor changes in the levels of the lake surface and the shallow lake-marginal groundwater can have an impact on geyser behavior.  Some geysers that were active during 2001 and 2005 had become weak hot springs or steam vents by August 2006 following a fall in lake level, whereas activity at other springs had increased.  At Loburu delta on the western shore of the lake, the geyser activity increased, and one of the geysers, KL30, erupted on a regular 45-minute cycle to 5 m height.  When active, KL30 is probably the highest natural geyser in Africa.  In contrast, a major rise in lake level in 2007 suppressed activity at many of the geysers, including KL30.

 The Short Active Period of “Improbable Geyser” October-November 2005

 By Stephen J. Eide

 Abstract:  “Improbable Geyser,” located on Geyser Hill, experienced a brief active phase in October and November 2005.  This article summarizes its activity describing major eruptions and physical changes in the geyser’s formation.

 The Behavior of the Grand Group During the Summers of 2005 and 2006

 By Vicki M. Whitledge and Ralph Taylor

 Abstract:  During the summers of 2005 and 2006 extra electronic data loggers were placed in the Grand Group.  These loggers recorded the activity of Turban Geyser and Grand’s pool.  Loggers were also in place on Grand Geyser, West Triplet Geyser, and Rift Geyser.  This paper analyzes the data obtained from these five loggers and discusses some of the relationships among these features.

 The Activity of Giant Geyser August 2005-April 2008

 By Tara Cross

 Abstract:  Giant Geyser had one of its best active phases in recorded history from August 2005 through April 2008.  A thorough study of reports, electronic data, and personal observations has been summarized.  The article discusses Giant and its related features; its major phases of activity from August 6, 2005, through April 29, 2008, focusing on the period from April 2006 through November 2007; and dominant patterns of activity during that time.

 Novel Methods for the Analysis of Grotto and Giant Geysers in the Years 2000 through 2007

 By Thomas F. Magnera

 Abstract:  The eruptions of Grotto and Giant Geysers for the years 2000 through 2007 are analyzed by methods based on the duty cycle, the reset time, the maximum energy efficiency, the Hilbert transform of a frequency-modulated telegraph series, and Grotto-to-Giant intervals.  Grotto’s transformation from a regular to irregular geyser after September 2005 is related to changes in the long-period modulation and increased average eruption duration.  The reset time and duty cycle concepts allow the division of Grotto eruptions into two new types, each associated with a distinct average reset time.  The Grotto-to-Giant interval analysis confirms a recent 9-hour rule for ‘recovery’ Giants, and puts a lower bound on the marathon interval that precedes an eruption of Giant.

 Changes in the Minor Activity of Geysers Prior to a Major Eruption

 By Jeff Cross

 Abstract:  Giant Geyser, Steamboat Geyser, Fan and Mortar Geysers, and Grand Geyser each erupt from complicated plumbing systems with two or more vents.  The quiet interval between major eruptions of these geysers is punctuated by cycles of minor activity.  During these cycles, the vents divide themselves into two groups which act antagonistically.  Just prior to the major eruption, the antagonistic activity is replaced by concerted activity from all the vents.  A hypothesis is presented to explain this observation.

 Baby Daisy Geyser Activity in 2003-2004

 By Ralph Taylor

 Abstract:  Baby Daisy geyser is located in the Old Road Group of the  Upper Geyser Basin .  It has had only three known periods of activity:  1952, lasting less than one year; 1959, lasting less than one year, and 2003-4, lasting from February 2003 to December 2004.  This paper discusses the 2003-4 activity as reported by observers between February and June of 2003 and as recorded electronically from June 2003 to the end of the active cycle in December 2004.

 Flood Geyser – Patterns Over Time

 By Lynn Stephens

 Abstract:  This paper describes eruptive behavior patterns of Flood Geyser.  It also presents evidence that Flood Geyser’s longer and stronger eruptions are succeeded by longer intervals.

 Activity of Excelsior Geyser, September 14-16, 1985

 By Mary Ann Moss

 Abstract:  During its active episodes in the 1880s and 1890s, Excelsior Geyser was undoubtedly one of the tallest, most spectacular geysers the world has ever known.  Historical accounts of Excelsior describe violent eruptions that were 300 feet tall and nearly as wide.  However, the brief active phase in September 1985 remains the only known instance of major eruptions of Excelsior since it fell dormant in 1901.  A few people were lucky enough to witness the 1985 activity, including Park Volunteer Mary Ann Moss, geyser gazer Mike Keller, and park employee Ed Wagner.  What follows are their personal accounts and photographs documenting the unique activity of September 15 and 16, 1985.  Mary Ann Moss was a volunteer for Park Geologist Rick Hutchinson, who asked her to take notes on the activity.  She has shared her recollections here, along with the detailed notes she took, her photographs, and the original memorandum from Hutchinson .  Supplementing this are additional photographs by Ed Wagner and a first-hand account by Mike Keller.

 Observations of “Underhill Geyser” in the Lower Geyser Basin

 By Stephen Michael Gryc

 Abstract:  “Underhill Geyser” (known earlier as “Dragonfly Geyser”) has a brief recorded history of eruptive activity, and this article is the first published description of the feature.  The author observed 32 eruptions over a period of two successive days in July of 2006.  A typical eruption is described and a table of timed activity is provided.

 Narcissus Geyser Eruption Patterns June 27-July 31, 2005

 By T. Scott Bryan

 Abstract:  Narcissus Geyser’s pattern of alternating long and short intervals has been written about since at least the early 1980s.  Electronic monitoring has made further analysis possible.  This article examines the interval and duration data in July 2005, concluding that Narcissus’ unusual alternating pattern of long duration-short interval, short duration-long interval eruptions existed over 96% of the time.

 Geyser Activity in the Upper, Midway, Lower, Gibbon and Lone Star Geyser Basins , and Other Thermal Areas, Yellowstone National Park, 1988-2006

 By Jeff Cross

 Abstract:  The recent history of over 60 geysers in Yellowstone’s backcountry and undeveloped frontcountry thermal areas from1988 through 2006 is presented. My observations are compared with other observations during and immediately prior to the years covered by this study.

 The Number of Geysers in Backcountry and Undeveloped Frontcountry Thermal Areas in Yellowstone National Park

 By Jeff Cross

 Abstract:  The object of this paper is to present a list of geysers that exist in the backcountry and undeveloped frontcountry thermal areas in Yellowstone National Park .  Although many of these geysers are listed in T. Scott Bryan’s The Geysers of Yellowstone, reference to additional sources shows that a total of 529 known geysers in backcountry and undeveloped frontcountry areas have been active at some time since the Park’s creation in 1872.  A detailed list of these 529 geysers, including name, location, and literature reference, is presented.