Davidof Volcano
{{Infobox mountain
| name = Davidof Volcano
| photo = Davidof.JPG
| photo_caption =
| elevation_m = 328
| prominence =
| listing =
| location = North Pacific, part of Alaska
| range = Aleutian Islands
| coordinates = {{Coord|51.9542|178.326|display=inline,title|region:US-AK_type:mountain}}
| topo =
| type = Stratovolcano
| age = Cenozoic
| volcanic_arc = Aleutian Arc
| last_eruption =
| first_ascent =
| easiest_route =
}}
Davidof Volcano is a potentially active stratovolcano and caldera remnant in the Aleutian Islands of Alaska, USA, {{convert|1237|mi|km|0}} from Anchorage.{{cite web|url=http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Davidof|title=Davidof description and statistics|publisher=United States Geological Survey|work=Alaska Volcano Observatory|access-date=July 15, 2009}} Located on the eponymous island, Davidof is part of the Rat Islands sub-chain. It is also part of the "Aleutian Krakatau", a group of four islands formed when a stratovolcano caved in during the late Cenozoic.{{Cite web |last= |first= |last2= |last3= |first3= |date=2021-12-11 |title=Earthquake swarm under Davidof volcano, U.S. |url=https://watchers.news/2021/12/11/earthquake-swarm-davidof-volcano-december-2021/ |access-date=2023-04-04 |website=The Watchers |language=en-US}}{{Cite news |title=Davidof Volcano – volcanoes – Alaska Handbook |language=en-US |work=Alaska Handbook |url=https://www.alaskahandbook.com/places/davidof-volcano/ |access-date=2023-04-04}}
In December 2021, an earthquake swarm was detected on the island, causing the Alaska Volcano Observatory to raise the volcano's alert level to Yellow. Another earthquake swarm, possibly a continuation of the first, was detected in late January 2022.{{Cite web |title=Davidof - Historic eruptions |url=https://www.avo.alaska.edu/volcanoes/activity.php?volcname=Davidof&eruptionid=4811 |access-date=2023-04-04 |website=www.avo.alaska.edu}}{{Cite web |title=Volcano earthquake report for Wednesday, 2 Mar 2022 |url=https://www.volcanodiscovery.com/earthquakes-volcanoes/news/174177/Volcano-earthquake-report-for-Wednesday-2-Mar-2022.html}}
Accessibility
Since the island is uninhabited, very little transportation is available. Transport can be found in Adak, albeit that the town is {{convert|199|mi|km|0}}Wood and Kienle, page 20. from the island.
Geography and geology
Because of the inclusion of Alaska, the United States has the largest number of active volcanoes in the world, many of them geologically young.{{cite web|url=http://pubs.usgs.gov/fs/2006/3142|title=The National Volcano Early Warning System (NVEWS): U.S. Geological Survey Fact Sheet FS 2006-3142|publisher=United States Geological Survey|author=Ewert, John |author2=Guffanti, Marianne |author3=Cervelli, Peter |author4=Quick, James|year=2006|access-date=July 9, 2009}} In Alaska, at least 50 volcanoes, including those in the Aleutian archipelago, have erupted in historical time.{{cite journal|url=http://www.dggs.dnr.state.ak.us/pubs/pubs?reqtype=citation&ID=16061|title=Alaska GeoSurvey News: NL 2008-1|publisher=Alaska Division of Geological & Geophysical Surveys|date=March 2008|access-date=July 9, 2009|volume=11|issue=1|pages=1–14}} Alaska accounts for about 80% of the United States' volcanoes, excluding the seamounts in the area, about 8% of the world's volcanoes, and most of these are located among the Aleutian Islands. The Aleutian Arc forms the northern boundary of the Pacific Ring of Fire, where tectonic activity generates earthquakes and volcanic eruptions regularly.
The largest of four tiny islands in the "Aleutian Krakatau" caldera,{{cite gvp|vn=311040|name=Davidof|accessdate=July 15, 2009}} Davidof is a stratovolcano and caldera remnant of a larger stratovolcano, which presumably collapsed at the end of the Cenozoic period. In all, the caldera extends for {{convert|262|ft|m|0}} underwater. Davidof Island's shape is abstract, with many inclining, steep features and several sea cliffs.Nelson, W. H., page 7. There are no visible water features.
Davidof's exact composition is unknown, although studies conducted by W.H. Nelson of the United States Geological Survey (USGS) determined that the lava, at least, was layered over a base of red breccia. The lavas appeared to be differentiating, but stuck to gray color with either "glassy or fine-grained, compact or dikty-taxitic" composition.Nelson, W. H., page 11. Much like Segula Island, all of Davidof's lava and even pyroclastic deposits interact by overlapping with each other. The uppermost layer of these deposits is formed by the pyroclastic flow deposits.
The lava is filled with phenocrysts like feldspar, olivine, and pyroxene, and these can be found easily about the lava areas.
= Eruptive history =
Although no eruptions have been recorded at Davidof, there is evidence of activity at the volcano. Through aerial photography, lava flow deposits have been detected among the flanks of the island. While the exact age of the deposits is still unknown, one source estimates that they are probably less than 10,000 years old.{{Cite journal|last1=Smith|first1=R.L.|last2=Shaw|first2=H.R.|last3=Luedke|first3=R.G.|last4=Russell|first4=S.L.|date=1978|title=Comprehensive tables giving physical data and thermal energy estimates for young igneous systems of the United States|url=https://pubs.er.usgs.gov/publication/ofr78925|journal=Open-File Report|doi=10.3133/ofr78925|language=en|issn=2331-1258|doi-access=free}}
Wildlife
Despite its small size, Davidof is heavily vegetated, with variations of moss, lichen, and heath.Nelson, W. H., page 8. Spread throughout the island are grass and sedges, which cover much of the lower surface. Fungi, liverworts, horsetails, and ferns, can be found on the island, along with flowering plants, such as the narcissus anemone, lupines, and orchids. Seaweed is also common on the island's beaches.
References
{{reflist}}
= Bibliography =
- Wood, Charles A., and Kienle, Jürgen, (eds.), 1990. Volcanoes of North America: United States and Canada; New York, Cambridge University Press, 354 p. {{ISBN|0-521-43811-X}}.
{{Authority control}}
Category:Volcanoes of the Aleutian Islands
Category:Landforms of Aleutians West Census Area, Alaska