The Buffalo Chip Resource Management Newsletter Yellowstone National Park Late summer 2003 What's inside East Fire threatens Fishing Bridge 6 Current BEMO projects 8 Historic sign raises eyebrows 10 UGB update 14 Arch event photos 15 Bear 101's new lite News briefs 20 WHAT'S UP AT NORRIS NOW? by Alice Wondrak Biol By now. many of you probably know that the Back Basin cording to personal observations, this feature has gone from trail at Norris Geyser Basin has been closed to travel due to being a milky, opalescent, quiet pool to a crystal clear pool, concerns for the safety of visitors and employees. Rumors roiling up to three feet in height. Pearl Geyser icccntl ha¥e abounded about this closure; we hope that the follow­ lowed the same pattern, then became a fumarole. Son vi ing information will clear up some questions that people Green Dragon, formerly a boi i i fumarole, providing researchers with a disturbing look at the astound­ ing amount of debris that people have thmwninto it over the .last the Facts years. Multiple features in the Back Basin have gone Effective July 23, approximately 5.S00 feel of trail earn; none of their temperatii; ling. prising most of the western portion of Norris's Back Basin On July 22. a new [hernial feature emerged near Son of .1 due to increased ground temperatures Green Dragon, emitting a mudflow that began spattering in the area—temperatures of up to hich is the boil­ boiling-temperature acidic mud (pH; 11 onto the trail, lead­ ing point noticeable changes leading up ing interpretive staff to immediately close the trail between to the closure began on July ll, when Echinus Geyser began t Green Dragon and Pearl (icyscr. That mudpot, also. apt regularly and changes in the ' . itnorole. The trail closure will remain in effect until ground tem­ Porkchop Gey. int since 1991 following a 19S9 peratures drop to what is determined to be a sale level tot had been heating up since April 2003. from 15 unloading data current 190° F At 5:10 p m. on July 16, Pnrkchop • ery few da Geyser erupted, and erupted again the next morn Echinus Geyser wenl through a period of regular eruptions following July 11 Lines A and B above show eruption intervals prior to and after that date (Ibscrvable changes ording to park geologist Hank few minutes. He recalls that when he Heaslcr, walking or standing on those and others first began gathering data on Much of the Back Basin trail leaves portions of the trail now becomes un­ the increasing ground temperatures, he the boardwalk and travels directly on comfortable and unpleasant after just a observed a family sitting on a bench the around, and visual changes in this portion of the trail wen what led re­ searchers to take a more careful look at the area's ground temperatures. Large, dark brown, hollow-sounding, moist spots began to appear on the usual I y white, dry sinter of the trail. As it was the middle of July, following four weeks without rain, this was deter­ mined to be unusual, and it was sus­ pected that the spots might have been the result of steam condensing beneath the trail. Another visual clue was the death of nearby trees and vegetation, accompanied by the sweet smell of vegetation curing as it cooked in areas both adjacent to and away from the boardwalk. The boardwalk itself start­ ed to turn charcoal-brown in some areas. and although some scientists have speculated that it may be related to the low water lev els that t mem then, no one is certain what triggers the annual dis­ turbance. If it were triggered by low water levels, the exceptionally dry summer wcither that this area has been experiencing could be an explanation, it might just be happening early, say some. Other questions include whether the warm-up might be related to the emer- I new thermal features at Nymph Lake, and Steamboat Geyser's increased eruption activity over the past year, or if the earthquake sw arm of Jan- iKiry 2002 (see tire March/April issue of the Buffalo Chip) may have altered the situated atop some of the ground later I hem ies abound geology of the area. On that last point. measured at 200° F, complaining about Bob Smith, of the University of Utah's the extraordinary heat of the day. The So are the changes at Norris just Yellowstone Volcano Observatory only one of them to realize (perhaps part of the area's typical dynamism, or (YVO), relates that seismic activity at unconsciously) that the heal wasn't just do they indicate something more un­ Norris has recently been some of the m the air may have been their son. a usual afoot? No one really knows. For quietist he's seen in 30 years. Norris is boy of about six, who kept raising Ins the park, the most important point b not totally devoid of tremors, of course, feet off the ground and into the air as if that the area needed to be closed in hut quakes have been few er in number to cool them. order to protect visitor safety. Answer­ than that to which he has become ac­ Park .scientists currently have eight ing questions beyond that is problem­ customed to seeing. temperature loggers (of the sort de­ atic, because although good data sets And what about the uplitt zone? scribed in the early spring 2003 issue of exist about Norris, there has been no The caldera boundary? The North- the Buffalo Chip) in place on the Back systematic, intense data collection ef­ South fault that runs between Norris Basin. Four arc deployed in about one fort there of the sort that would allow and Mammoth? Header reports that the inch of earth on the trail, to segregate scientists to delenmne whether what's new thermal vent at Nymph Lake is lo­ them from the air temperature, which is cuirently happening falls within the pa­ cated at the edge of the uplift ZOOS, It is measured hy another logger. When rameters of "normal" events at Norris. also true that the 2.1 million-year old downloading the data from these log- Thus, no causative mechanism tor the caldera boundary established by now- i, staff are required to wear leather increased temperatures has been iden­ retired USGS geologist Bob Chris­ boots with wool socks. Synthetic socks tified. tiansen runs through Norris, possibly are not permitted because of their po­ Some people have been pointing to indicating a tendency toward geologi tential for melting under high tempera­ what's come to be known as the "an­ cal instability. And some people say tures. Gaiters are worn over the boots nual thermal disturbance" at Norris—a that the waterworks of Norris and and pants to prevent the boots from Fill­ noticeable change in the color and Mammoth Hot Springs may be con­ ing up with water in the case of some­ steam discharge of many of Norm's nected via the fault line that links them. one's breaking through the crust. De­ existing geysers and thermal pools oc­ All of these ideas arc worthy of explo­ spite the summer heat, staff must w car curring each year that may be related to ration; the goal now is to collect the a full outer layer, including gloves and increased emission of deep, hot waters. data that will help us begin to support a jacket, when sampling thermal fea­ Many recent observations fit within the or refute them. tures. They arc also spending time pol­ parameters of the annual disturbance Partnering for baseline data ishing up their NPS badges, which tend Porkchop Geyser's temperature in­ to tarnish with prolonged exposure to crease, for instance, is not an unusual Of course, that is easier said than thermal gases. Data from the ground occurrence during the annual distur­ done. gi\ en the aforementioned lack of loggers have been showing a constant bance. On the other hand, the annual malic data collection. Through its 200° F throughout the day. disturbance typically OCCUR in the fall. partnerships with the USGS and the 3 University ol'Utah, however, the NPS Following the installation of the n response to the increased heat is beginning m change all that When seismometers and additional GPS sta­ and steam emissions in parts of NPS researchers first realized the po­ tions (which will be deployed within a INorris Geyser Basin, the Yellow­ tential threat posed by the recent 500-meter radius of Vixen Geyser and stone Volcano Observatory is de­ changes at Norris. they passed the in- allow scientists to chart surface move­ ploying a temporary network of seis­ formatiun along to researchers at the ment, e.g., changes in the uplift i. mographs, Global Positioning Sys­ YVO. jointly operated by the NPS. Heasler expects thai scientists will be tem IGPS1 receivers, and tempera­ USGS, and University of Utah. The able to document all thermal events ture loggers The temporal deploy­ partnering agencies immediately set better than before; have a better chance ment is intended to documem about creating a plan for how to better at determining whether they are "nor­ chemical and physical signals that document events at Norris. as well as mal;" and improve our knowledge of accompany this increased activity, to determining what their longer-term im just what's going on in the "upper 100 identify the underground locations of plications might be. A great amount of meters" below Norris, with informa­ hydrothermal steam sources and time and effort, including sometimes- tion that is published and reproducible the relationship of the Norris Geyser nightly calls among scientists, resulted by other scientists, as well as available Basin to the background general in a more aggressive scientific moni­ nierpretation and debate by a wide seismicity, and crustal deformation toring plan that will be co-sponsored range of scientists.