Passage IV

Karymsky Lake is located within a volcanic caldera (a wide basin, formed when the peak of a volcanic cone collapses). In April 1993, water samples were collected from the lake and analyzed for pH, for Na⁺, and for SO₄²⁻. On January 2, 1996, a 2-day-long underwater eruption occurred in the lake. The eruption produced a crater on the bottom of the lake at the north end (see diagram). In April 1996, water samples were again collected from the lake and analyzed for pH, for Na+, and for SO₄²⁻.

Study 1

On April 1, 1993, in the center of the lake, a set of water samples was collected at the surface (0 m depth) and at each of the following depths: 10 m, 20 m, 30 m, 40 m, 50 m, and 60 m. For each of the 3 analyses, the measurements were averaged for the set of water samples from each depth. The results for pH, and for Na⁺ and SO₄²⁻ contents, in milligrams per liter (mg/L), are shown in Figure 1.

Study 2

On April 1, 1996, Study 1 was repeated, except at 2 locations in the lake—at the center of the lake where samples were collected in Study 1, and within the newly formed and flooded volcanic crater. The results are shown in Figure 2.

Figures adapted from S. M. Fazlullin et al., “The 1996 Subaqueous Eruption at Academii Nauk Volcano (Kamchatka) and Its Effects on Karymsky Lake." @2000 by Elsevier B.V.