Bogoslof reported activity

Event Name : Bogoslof 1909/9

Start:	September 1909	Observed
Stop:	September 19, 1910	Observed

Tephrafall:
Lava dome:
Tephra plume:
Island-forming:
Submarine:
"Fire", "Glowing", or incandescence:

Eruption Type:	Explosive
Duration:	About 1 year
Eruption Product:	andesite
MaxVEI:	2
Chem	Yes
Other	mafic

Description: Miller and others (1998) summarizes the September 1909-1910 eruption of Bogoslof as follows: "Yet another conical islet, Tahoma Peak, was formed during the winter of 1909-1910 in the bay created by the destruction of McCulloch Peak. Explosions in September of 1910 produced a deep crater at its summit (Byers, 1959); this was apparently the first documented crater in a Bogoslof dome (Jaggar, 1930)."

Powers (1916) relates the following detailed information: "Renewed activity in the bay between Old Bogoslof and Fire Island is reported in September, 1909. The bay had closed to form a lagoon, in which two small islands had risen, once of which gave off steam. The water in the lagoon was also constantly steaming. The two small islands were apparently just beginning to rise as new rocky spines, for on June 16, 1910, they are reported to have united and risen to a height of 178 feet above the lake level. Old Bogoslof, Fire Island, and the southwest shore of the lagoon remained the same as in the preceding year, but the new spines had become connected with the northeast shore of the lagoon, and a portion of the shore on that side had risen ten feet. Although the temperature of the salt lagoon ranged from 62 degrees to 100 degrees F., there was little activity in the new rock-masses and water was boiling up from only a few places near the lagoon.

"A survey of Bogoslof Island was made on September 10, 1910, under the direction of Captain J.H. Quinan of the U.S. Revenue Cutter Tahoma, showing that the island was about one and a half statute miles long and three-quarters of a mile wide, as shown in Figure 2. The elevations of the peaks were: Fire Island, 175 feet, Castle Rock (Old Bogoslof), 289 feet; the higher of the two central peaks, 178 feet; the lower, 100 feet. The lower of the central peaks is given the name Tahoma Peak by Captain Quinan in his report, and the higher is called Perry Peak in spite of the fact that the remaining portions of Perry Peak were reported to have disappeared by July , 1908. [There is some discrepancy about when Perry Peak disappeared; Powers says by July, 1908, while other sources say it disappeared by September, 1908] In view of the records given above, it seems probable that Captain Quinan saw a new peak which rose in 1909-10 in the same place that Perry Peak occupied from 1906-08. No name is suggested for this new peak.

"Steam issued from the base and sides of the new peaks at the time of the visit, and steam was issuing from the salt lagoon shown on the map. Between the new peaks and Fire Island, in the mud-covered area near the small lagoon, an area of several hundred yards was in violent agitation. Boiling water was being ejected through the mud, and in two pools, each about four feet in diameter, water was being thrown to a height of five feet by the rapidly escaping steam. Another seat of activity was on the northeast side of Tahoma Peak, at the edge of the main lagoon. Explosions had recently taken place here, according to Captain Quinan's report, and a group of steaming conical rocks had risen since the explosion. The water around these rocks was boiling, but not so violently as near the smaller lagoon.

"* * * [F]ortunately Captain Quinan sailed back toward the island on September 18, and when about twenty-five miles away in the early morning witnessed an eruption. Forked lightning in the direction of Bogoslof was seen before daylight, and when Bogoslof was sighted the new central peak was seen to be in a state of eruption. Immense clouds of vapor, smoke, and ashes issued from the peak and enveloped the entire island. Flames were reported at the peak, and lightning followed by thunder appeared in the cauliflower cloud of smoke and volcanic dust which rose to a height of several thousand feet above the island. The eruption lasted during the several hours the steamer remained in the vicinity, and two days later the central peak was observed to be still steaming.

"The eruption of September, 1910, seems to have opened a true crater in the top of the central peak - the first important crater which has been reported on any of the masses of very viscous rock which have been slowly pushed out from the top of the submarine volcano to form the "rocks' and "peaks" of the last hundred and fifty years."

Hunnicutt (1943) reports more colorfully on the experiences of Captain Quinan and his crew, stating "the Tahoma experienced a violent electrical storm. Saw molten lava, rock, steam, and smoke shooting into the air from the center of a salt lagoon that had been formed on one spur of the island. The wind created by the disturbance could be felt for several miles. Red-hot lava literally covered the Tahoma with volcanic sand and pumice, and the ship made for the leeward of the island, about six miles, where the temperature was uncomfortably warm. So much lava fell on the ship it had to be hosed down. (September 1910). The Tacoma returned several weeks later, and found a land of hot ashes and baked mud, and from the center a great column of scalding water spouted. There was still a loud rumbling form beneath the surface and it was so loud the men, when standing only a few feet apart, had to shout at each other to be heard. There was pitiful evidence of the terrific heat, for bird skeletons were found in great numbers lying about the island where they had been veritably roasted alive. The heat and the fumes had been so potent that the tiny skeletons disintegrated into fine powder when an attempt was made to pick them up."

Powers (1916) states that there are no reports on Bogoslof for 1911 or 1912.

Newhall and Melson (1983) estimate that the volume of the Metcalf, McCullogh, and Tahoma Peak lava domes (1906-1910) was about 5x10^6 cubic meters.