The Flickr Umnak Image Generatr

Brooks Fuel C-54G N51802 parked at Umnak-Ft. Glenn Airstrip awaiting cargo for Dutch Harbor during a sunny, winter day.

These are seismograms for the Maple Creek and Parker Peak seismic stations in Yellowstone, Wyoming. The noise on the 09:30 lines was produced by shock waves from two Alaska-area earthquakes.

The first event (at left on the charts) was a magnitude 6.4 subduction zone earthquake that hit a bit offshore from Umnak Island in the Aleutians. It occurred at 7:22 AM, local time, on 1 December 2020. The first seismic waves arrived at Yellowstone 7 to 7.5 minutes later at 9:29 AM, Yellowstone time. The hypocenter was at about 23 kilometers depth.

The second event was ~13 minutes later - a magnitude 5.7 earthquake that hit way offshore from southern Alaska. The epicenter was east of Hecht Seamount and south of Patton Seamount. The quake occurred at 6:35 AM, local time, on 1 December 2020. The first seismic waves arrived at Yellowstone almost 6 minutes later at 9:41 AM, Yellowstone time. The hypocenter was at about 42 kilometers depth.
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See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000clnv/exec...
and
earthquake.usgs.gov/earthquakes/eventpage/us7000clp0/exec...

This is a seismogram for the Maple Creek seismic station in Yellowstone, Wyoming. The prominent noise on the 22:00 line (click on the image once or twice to zoom in) was caused by shock waves from a magnitude 5.6 earthquake that hit south-southwest of Umnak Island, offshore from the Aleutian Islands, Alaska. The quake occurred at 7:12 PM, local time, on 26 September 2020. Shock waves arrived at the seismic station at 10:19 PM, Yellowstone time, ~7 minutes after the quake hit. The hypocenter area was almost 14 kilometers deep.

This was a subduction zone earthquake. Subduction zones have a tectonic plate composed of oceanic lithosphere diving underneath a plate of continental or oceanic lithosphere. In this case, the oceanic Pacific Plate is subducting beneath continental lithosphere of the North American Plate. Subduction zones have the most powerful tectonic quakes in the world. Quakes and volcanism are common geologic hazards in such settings. The subduction zone itself is a deep seafloor trough next to the Alaska Peninsula and the Aleutian Islands chain - the Alaska-Aleutians Trench. Active and potentially active volcanoes occur throughout this part of Alaska.

See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000c1tj/exec...
and
en.wikipedia.org/wiki/Aleutian_Trench
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.

Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).

Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.

Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.

Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.

With World War II approaching, Consolidated Aircraft, which had only built flying boats to this point, was approached by the US Army Air Corps to license-build Boeing B-17 Flying Fortresses. Reuben Fleet, president of the company, felt he could do better than Boeing’s design. The USAAC accepted the Model 32 as an interim aircraft between the older B-17 and the very long range bombers already on the drawing boards, such as the B-29 Superfortress. As stipulated in the contract, the XB-24 had to be ready for flight before the end of 1939, giving Consolidated only ten months. They delivered with the new bomber flying only a few days before year’s end.

The XB-24 was roughly the same size as the B-17, though with a longer wingspan, tricycle landing gear, and twin tails. The innovative part of the bomber was its wing. Known as the “Davis Wing” for its designer, the wing design was over 100 percent efficient. To lighten weight and increase range, the entire wing was used as a fuel tank, in the world’s first “wet wing.” To further streamline the design, the bomb bay doors rolled up into the slab-sided fuselage rather than open into the airstream as on other bombers. Fleet felt that the prototype was “too ugly” and had another three feet added to the nose for aesthetic reasons. While it did not do much to improve the XB-24’s looks—both friend and foe would refer to them as “furniture vans”—it partially alleviated what was already a very crowded nose.

Before the XB-24 had even flown, its potential was such that over 300 were ordered by the USAAC, the Royal Air Force, and Armee de l’Air (the latter never delivered before France fell to Germany in 1940, and sent to the RAF instead). It would be the RAF that would give the B-24 its name—Liberator—and its introduction to combat. Unlike the B-17, the British never attempted to use the B-24 over Europe, instead converting it to a maritime patrol aircraft, utilizing the Liberator’s long range. This range allowed RAF Coastal Command to finally close the infamous “Black Gap” in the mid-Atlantic where U-boats had roamed freely on the surface, as no Allied aircraft had the range to reach them there. The RAF would use their early B-24As as LB-30 transports, and later deliveries as Liberator GR.V variants, with searchlights and rockets that would prove deadly to U-boats caught on the surface.

Also unlike the B-17, the B-24 would have a longer
introduction period to American wartime service. Though the US Army Air Force had about two dozen in the Pacific in early 1942, they were not used extensively. It was planned for a small 12-plane unit of B-24s, the Halvorsen Provisional Detachment (or Halpro) would attack Tokyo from bases in China, but Halpro never made it past North Africa, where it was used to support the British victory at El Alamein and raided the vital Romanian oil facilities at Ploesti—Nazi Germany’s “gas station” and a harbinger of things to come.

By late 1942, B-24s began to be mass produced with the B-24D variant, which increased the type’s defensive armament and built on improvements made in the B-24C. This introduced supercharged engines, giving the B-24’s powerplant its distinctive flattened-elliptical shape (as opposed to circular engines on the B-17 and early B-24s), and a belly turret, initially a dizzying remote turret and then a manned “ball” turret. The latter was an improvement over the B-17s as it could be retracted into the fuselage. Once introduced to combat with the 8th and 15th Air Forces, the B-24D was found to be able to fly higher and faster than the B-17, as well as carry more bombs; in fact, the B-24 had to slow down so as not to outdistance the B-17 groups. The aircraft was not without fault, however: it was much tougher to fly than the B-17, and could not sustain damage as well—the wet wing caught fire and exploded with depressing regularity under fire, bailing out was very difficult for the flight crew, and impossible to ditch without disintegrating. It was still very much a workhorse alongside its older “stablemate,” the B-17.

B-24s would see heavy service worldwide, replacing the B-17 entirely in the Pacific and supplementing it over Europe. B-24s would bomb both Berlin and attack the southernmost Japanese home islands. Besides acting as strategic bombers, Liberators would also act as antisubmarine maritime patrol aircraft for the RAF, the USAAF, and the US Navy as the PB4Y-1; the latter would also be converted to primitive cruise missiles in Operation Aphrodite against German V-weapon sites in Belgium. One Aphrodite mission would claim the life of Joseph Kennedy Jr., older brother of future President John F. Kennedy. By 1945, it was possible to find B-24s literally everywhere, from Alaska’s cold Aleutians to sunny Brazil, from China to Italy.

After the end of World War II, the USAAF rapidly scrapped nearly its entire B-24 fleet, but a few soldiered on in the 1960s, mainly in India, where they operated as maritime patrol aircraft. Others served as seed aircraft for postwar airliners, including Qantas of Australia. By 1968, however, nearly all B-24s had disappeared from inventories worldwide; today, only 14 complete Liberators are left, with two aircraft flyable.

One of the oldest B-24s left, this is 41-23908. Not long after delivery in late 1942, it was assigned to the 28th Composite Group at Umnak Island, Alaska; the 28th's job was long-range maritime patrol and interdiction of Japanese efforts to resupply their small garrisons on Attu and Kiska. It was quite possibly the most miserable theater of the Pacific theater, where more died due to the weather than enemy action. On 18 January 1943, 41-23908 was returning to a forward base at Adak when mechanical issues forced it to belly land on Great Sitkin Island. The crew was rescued and the aircraft was abandoned to the elements.

50 years later, after hearing stories of a semi-intact B-24 on Great Sitkin, the wreckage of 41-23908 was located in 1994. It was in surprisingly good condition, considering it had been exposed to the elements for five decades. A recovery expedition funded by the Aerospace Heritage Foundation of Utah and the USAF recovered the aircraft in 1995 over a period of several months, and it was sent by ship to California for restoration. In 2002, the fuselage arrived at Hill AFB and went on display; by 2017, the wings were attached and the B-24 was considered practically complete.

I was looking forward to seeing 41-23908, if for no other reasons than I had seen the fuselage in 2002 and there are so few B-24Ds left. It is displayed in a diorama, with two female mannequins performing an engine check on the starboard side. The brighter shade of green over gray seems a little too bright to me, but there were so many field schemes for B-24s that it could be entirely accurate, especially for 1942.

Unfortunately this was the last picture my camera took before it finally pooped out, so it blurred. Naturally--one of the reasons I came to the Hill AFB Museum, and the camera goes out... EDIT: Luckily, I was able to make a return trip to Hill in June 2022, and replace it with a much better shot.

Located just West of Fort Glenn on Umnak Island. Have to enlarge to see it.

The cattle roam free on the island

I am told that this is Mount Recheschnoi

WWII Fort Glenn Army Air Base located on Umnak Island in the Aleutians. Constructed between January and April 1942 and decommissioned in 1950.