ERUPTION OF 1886.
The Halemaumau pit was completely filled up on the evening of March 6th, 1886. The lava that for nine years, or since the last previous important discharge (1877) had been accumulating and pouring over the floor from Halemaumau and New Lake, the latter five years old, attained the altitude of about 3,710 to 3,730 feet above the sea. The bottom of the pit of Kilauea was con vex—the top being about one hundred and sixty feet higher than at the northern edge, while the general level averaged from two hundred and fifty to three hundred feet above the black ledge of IUD. Much of the old sulphur bank had been covered and the precipice at the southwest corner had mostly disappeared. Late in the evening there commenced a series of earthquakes so severe as to alarm J. H. Maby, of the Volcano House, and his family. Forty-three shocks were noted up to 8 A. M. of the 7th instant. After the fourth quake the light disappeared.
For three days the heated vapors had been uncommonly hot, but on the 6th and 7th instant ceased entirely. About midnight the lava disappeared. Plate 38i may show the convex outline before the eruption and Plate 38 2 the appearance of the contour afterwards. At first, however, the walls must have been more nearly vertical. Later large blocks of the black lava fell down, and there was a talus on all the steep slopes. From five hundred and seventy to five hundred and eighty feet thickness of rock fell away directly beneath the Halemaumau lake. The adjacent New Lake was comparatively shallow, one hundred and fifty feet. The central pit was about three hundred feet in diameter. Plate 36 shows the appearance of Halemaumau after the withdrawal of the lava ; and Plate 37A a ground plan of the triangular area affected.
Compared with the earlier discharges this was very small. The main depression is of triangular shape with sides about 3,35o feet long, forming an area less than half a mile square. In extent it is not very unlike Kilauea iki, though the basin carries less cubical content. On the east side there is a rudely semicircular depression where New Lake was, with its floating islands of rock. It makes a sort of shelf averaging one hundred and sixty five feet in depth. The entire floor of the caldera is now the black ledge and the lower pit only the diminutive half a mile square area of Halemaumau ; and the mass that has disappeared is so small that it is hardly worth while to seek to discover where it has gone.
It is to be expected that the liquid might ooze from one of the great fissures extending southwesterly for several miles towards Pahala, and be scarcely noticed as the region is mostly a barren uninhabitable waste. In my of this eruption, June 7 to 14, I have stated that besides the formation of the pit there were produced several large fissures in the neighborhood ; one on the Poli o Keawe, at the sulphur banks near the Volcano House, and two on the road to Keauhou, two miles distant.
Mr. J. S. Emerson was at Kilauea between March 24th and April 14th, taking measurements for a map. He saw no molten lava, but could discern evidences of heat. Rev. Mr. E. P. Baker and Mr. Emerson both descended into the pit. On the eighth of June I descended to its very lowest depth, nine hundred feet be low the Volcano House. To the depth of about three hundred and twenty-five feet, embracing nearly all the triangular area, the sides were covered by irregular slabs of pahoehoe, six or seven feet long, four or five feet wide and a foot thick. These were the crust of the lava at its greatest development, and they naturally fell on the slope so as to lie quite uniformly, though some frag ments were tilted in every direction. The small lower pit, some six hundred feet across, was covered by the ordinary grayish lava blocks, and there were small jets of vapor. On the east side of this pit on June 8th, I found a hole about four feet in diameter, nearly vertical, reaching down perhaps as deep as the pit, to a mass of molten lava. Great volumes of steam and sulphur vapor poured out of this orifice, whose walls were lined with sublimed sulphur and Pele's hair. As this opening was situated in the midst of loose blocks of rock and widened out downwards, it was dangerous to stand near it ; but the swashing of the liquid was distinctly audible and stones thrown down were heard to splash into the liquid. By my advice my companion withdrew from the edge of this opening, and immediately afterwards the rim fell down into the fire. Had not my friend taken my advice he would have lost his life. About two hundred feet northwards from this opening there was a copious discharge of corrosive vapors, which increased in strength in the course of the following week. The fire in this opening continued to enlarge by absorbing the walls. June 25th two vents opened upon the west side of the pit, and lava flowed from the well originating June 8th, filling up the pit.