Non-volcanic mountains in southeast Alaska.
Mt. Calder, Bucareli Bay, Southeast Alaska:
In 1775, Francisco Mourelle reported that while anchored in Bucareli Bay "The nights are extremely bright and mild, because of seven volcanoes of snow and fire,
which with their vapors illuminate and temper it" (Olson, 2002). Olson (2002) notes that this observation is ". . . most puzzling. On a chart supposedly based on
this observation, the note 'Land of Volcanoes' is inscribed north of Bucareli Bay. This writer has consulted with several Alaskan geologists and they all agree
that there were no known volcanoes erupting in this area at this time in history. . . . Dee Longenbaugh, a well-known Alaskan historian, has suggested that perhaps
there was a forest fire burning behind the hills or mountains to the north. Mourelle's volcano observations are not corroborated in the journals of others present
on the voyage, nor are they repeated when he revisited Bucareli Bay in 1779."
Because Mt. Calder is a prominent peak located north of Bucareli Bay, Grewingk (1850) and subsequent compilers attributed Mourelle's 1775 observations to Mt.
Calder. Mt. Calder is composed entirely of Silurian and Ordovician sedimentary rocks, and is not volcanic (Gehrels and Berg, 1992).
References:
- Gehrels, G. E., and Berg, H. C., 1992, Geologic map of southeastern Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I 1867, 24 p., 1 sheet, scale 1:600,000.
- Grewingk, Constantine, 1850, Grewingk's geology of Alaska and the Northwest Coast of America [edited by Marvin W. Falk, translation by Fritz Jaensch published 2003]: Rasmuson Library Historical Translation Series 11, Fairbanks, AK, The University of Alaska Press, 242 p.
- Mourelle de la Rua, F.A., 1781, Journal of a voyage in 1775 to explore the coast of America, northward of California: J. Nichols, London, p. 471-534, 1 chart.
- Olson, W.M., 2002, Through Spanish eyes: Heritage Research, Auke Bay, AK, 576 p.
Mt. St. Elias, Mt. Crillon, and Mt. Fairweather:
Early explorers to Alaska often located the highest peaks in a region and called them "volcanoes." Early exploration reports of "black stripes on the snow" of Mt.
St. Elias (Collie and others, 1839) were probably due to snowmelt and vegetation rather than volcanic ash. We now know that these peaks are not recently volcanic;
Mt. St. Elias is composed of schistose metamorphic rock; Mt. Crillon is composed of Tertiary gabbro and Cretaceous volcanics; Mt. Fairweather is composed of
sedimentary and intrusive rocks (Winkler, 2000 ; Gehrels and Berg, 1992; Plafker and MacKevett, 1969). However, even in 1850, the assertions that Mt. St. Elias and
Mt. Fairweather were volcanoes were challenged; Grewingk (1850) writes that he examined all available travelogues and couldn't find any mention of volcanic activity
at either of these peaks.
References:
- Collie, Alexander, Belcher, Edward, and Sir William Buckland, 1839, Notices on the geological structure of the numerous and distant points of the globe visited by Captain Beechey on his late voyage, selected by Professor Buckland from the notes: H.G. Bohn, London, p. 158-180.
- Gehrels, G. E., and Berg, H. C., 1992, Geologic map of southeastern Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I 1867, 24 p., 1 sheet, scale 1:600,000.
- Grewingk, Constantine, 1850, Grewingk's geology of Alaska and the Northwest Coast of America [edited by Marvin W. Falk, translation by Fritz Jaensch published 2003]: Rasmuson Library Historical Translation Series 11, Fairbanks, AK, The University of Alaska Press, 242 p.
- Plafker, George, and MacKevett, E.M. Jr., 1969, Mafic and ultramafic rocks from a layered pluton at Mount Fairweather, Alaska: U.S. Geological Survey Open-File Report 371, 15 p.
- Winkler, G. R., MacKevett, E. M. Jr., Plafker, George, Richter, D. H., Rosenkrans, D. S., and Schmoll, H. R., 2000, A geologic guide to Wrangell-Saint Elias National Park and Preserve, Alaska: A tectonic collage of northbound terranes: U.S. Geological Survey Professional Paper PP 1616, 166 p.
Location of Torbert.
Mt. Torbert
On July 9, 1953, Mt. Spurr near Anchorage, Alaska, erupted, showering Anchorage residents with ash. Initial newspaper accounts of the event declared "CITY BLACKED
OUT BY 3 VOLCANOES!" and claimed that Mount Spurr, Mount Torbert, and a third, unnamed peak were all erupting. Mount Torbert is about 9 miles northwest of the
summit of Mount Spurr, and about 11 miles northwest of Crater Peak (the vent on Mount Spurr that erupted in 1953). Mount Torbert and the unnamed peak are not
volcanoes, and were not erupting. Subsequent newspaper articles of the time continue to list Mount Torbert as erupting, and a New York Times article also wrongly
claims that three volcanoes were erupting, possibly four.
The first scientific publications of the event attempt to set the record straight. Wilcox (1953) writes: "The eruption took place from an old ice-filled vent at
an elevation of about 7,000 feet on the south shoulder of Mount Spurr [Crater Peak], about 80 miles west of Anchorage, Alaska. Reports of concurrent eruptions
from other points on Mount Spurr and Mount Torbert, must be regarded with suspicion, for nothing in the subsequent pattern of ash deposits on the snow in the area
supports these reports, and no new snow had fallen before the observations were made (Juhle and Coulter on July 11 and Wilcox on July 12) that might have obscured
the ash from other vents."
Subsequent study by AVO geologists has determined that there are no historically active volcanoes within 50 miles of Mount Spurr, and that Mount Torbert is not a
volcano.
Unfortunately, references to Mt. Torbert erupting proliferate to this day - as in the erroneous "Alaska Remembers" article in the November 2003 article of Alaska
Magazine.
References:
- Associated Press, 1953, Anchorage is darkened by ash of 3 volcanoes: The New York Times, July 10, 1953, section L, p. 21.
- Unknown, 1953, City blacked out by three volcanoes!: Anchorage Daily News, v. 6, n. 57, front page, July 9, 1953.
- Wilcox, R. E., 1953, Preliminary report of the eruption of Mount Spurr Volcano, Alaska, July 9, 1953, and the ashfall in the Anchorage area: Denver, CO, U.S. Geological Survey, 22 p.