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The underwater eruption in the Academia Nauk caldera (Kamchatka) and it consequences

S.M. Fazlullin, S.V. Ushakov, R.A. Shuvalov, A.G. Nikolaeva, E.G. Lupikina
Institute of Volcanology, Far East Division, Russian Academy of Sciences,
Petropavlovsk-Kamchatsky, 683006, Russia

Masahiro Aoki
Mineral Resources Dept., Geological Survey of Japan, Higashi 1-1-3, Tsukuba 305, Japan,

ABSTRACT: A unique event- an underwater eruption in the Karymskoe fresh-water lake (in the Academia Nauk caldera)- was studied by scientists from the Institute of Volcanology. Geomorphologic, hydrological, hydrochemical and hydrobiological investigations were conducted. This publication contains the general first results of the investigation of this phenomenon.


In the beginning of 1996 on Kamchatka a simultaneous eruption from two volcanic craters, located six kilometers from one another, was observed. One of them was in the crater of Karymsky volcano, while the other was in the northern part of Karymskoe caldera lake. As a result of the eruption an accumulated volcanic structure was formed in the northern part of the lake.
Investigations permitted the determination of the characteristic peculiarities of the lake's post-eruption morphometry. A map of depth-contours in the lake and crater, formed in the lake's northern part, was constructed (fig. 1). Microelement composition analysis of water samples was conducted under the leadership of Dr. Aoki of the Geological Survey of Japan. Macroelement composition was determined in the chemical Laboratory of the Institute of Volcanology.


The eruption was proceeded by an increase in seismologic activity, beginning in April, 1995. On December 31, 1995 at 19:26 local time an earthquake with magnitude 5.8 occurred in Kronotsky Bay, which is located 50-60 km north-east of Karymsky volcano. On January 1, 1996 at 20:57 an earthquake of magnitude 5.2 was registered near Karymsky volcano and at 21:57 an earthquake of magnitude 6.9 was registered 25 km to the south of Karymsky volcano (Fedotov S.A., 1996). Over the next few days an earthquake swarm with magnitude > 5.0 was registered in this zone. Near midnight on January 2, 1996 an eruption began in the crater of Karymsky volcano and after 14-15 hours an underwater eruption commenced in the northern part of Karymskoe lake. According to available information (Fazlullin, 1996, Karpov et al, 1996) the underwater eruption in the Karymskoe lake began on January 2, 1996 between 14:00 and 15:40. It has been established that the surface of the lake was free of ice at midday on January 2, while one week earlier an ice layer was observed.
Aerial observations were conducted at a distance of 5-7 km between 15:40 and 16:20. A gas-ash trail rose up to 3 km and spread to the south-east, in the direction of the Pacific ocean. Ash fall from the trail covered hundreds of square kilometers. Simultaneously, in the northern part of the Academia Nauk caldera, steam and gas loaded with a dark material (presumably, volcanic ashes and lake sediments) rose in columns above the lake with a frequency averaging once every 5-6 minutes(Karpov, 1996). In the process of the volcanic expulsions a cupola-like cloud with a diameter of 200-300 m formed. Over the course of several seconds the cloud changed its form. A basic wave in the form of a taurus-shaped cloud spread to all sides from the eruptive center. Its top edge was approximately 100m high. At the same time, a white gas-steam plume extended upward 7-8 km from the eruptive center. Each series of underwater explosions was accompanied by the formation of waves on the surface of the lake, some of which reached several meters in height. The energy of one explosion, as calculated by S.A. Fedotov (Fedotov 1996) according to the maximum height of the gas-ash clouds, reached 1014 J. As a result of the eruption, a flood occurred in Karymsky River, which flows out of the lake. A significant part of the caldera of Karymsky volcano, adjacent to the river valley, was covered in a mud flow.
On January 3, explosive activity in the lake stopped. According to our calculations, the activity lasted a total of 12-14 hours. The entire surface of the lake steamed, and the steam reached a height of 800-1000m. In the northern part of the lake, a beach of erupted material was formed, creating a new coast line. Plumes of fumarolic gas rose from several vents on the surface of this beach.

Characteristics of the lake, based on observations of Sept.,1996


Length, m                                              4050

Maximum width, m                                       3750

Average depth, m                                        47

Maximum depth, m                                      61-62

Area of the water surface, km2                          9.8

Coast line, km                                         12.5

Volume of the lake water, million. m3                 460.6

Volume of water in the new crater, million. m3          5.1

Volume of the new volcanic structure, million. m3      60.1

Angle of the lake sides, degree                       12-15

Average angle of the crater, degree                     12


Water level in the lake changed by several meters. The flow of the Karymsky river from the lake was blocked by a dam, formed from erupted material. Several tens of square kilometers of land about the lake was covered by material brought by polluted rain, formed from lake water and eruption products. At a distance of several hundred meters from the center of the underwater eruption, impressions of various size, formed by falling bombs and other material, were noted in the snow (Karpov, 1996). The waves created by the eruption removed the snow cover on the shoreline, in places up to 15-20m above its surface. In many places on the coast land slides and an absence of top soil were noted. The inner slope of the Academia Nauk caldera, adjacent to the zone of the eruption, suffered most of all. Tens of thousands of cubic meters of soil were eroded by water. Intensive influence of materials from the underwater eruption damaged plant cover over an area of several square kilometers, covering everything with a layer of mud. The underwater eruption was a catastrophe for the lake’s biota. The enormous waves, along with the sharp change in chemical composition and water temperature, lead to the death of practically all life in the lake.

In order to calculate the amount of heat energy released during the course of the underwater eruption, we used the vertical temperature distribution and hydrochemical characteristics of early May, 1996. Persistent stratification existed in practically the whole lake, excluding the new, water-filled crater. An analysis of the particularities of the vertical temperature distribution and mineralization in the lake showed that the water layer below the thermocline formed as a result of the January eruption, and has undergone little change since then. According to our calculations, the underwater eruption released more than 11.8x1015 J of heat over the first two days of the eruption.


As a result of the underwater eruption, the hydrochemical characteristics of Karymsky Lake changed drastically over the course of several hours (table 1).


Table 1. Water composition in Karymsky Lake in various years (before and after the eruption) in mg/l 


elements	 1	 2	 3	 4	 5   	 6	 7

   H+		0,58	0,6	0,62	0,64			

  NH4		0,2	0,2	0,2	0,2	0,0	0,0	0,05

   Na		65,3	64,4	73,0	64,6	14,2	10,4	322,0

   K		6,6	6,7	6,6	6,6	1,7	1,6	23,5

   Ca		64,0	64,0	63,2	63,2	3,6	1,6	4,8

   Mg		18,9	19,3	18,4	18,4	3,16	0,5	0,2

   Mn		1,94	1,94	1,92	1,92			

  Fe3+		6,1	6,1	6,1	6,1			

  Al3+		4,9	4,9	4,9	4,9	d.l.		

   Cl		40,5	39,0	38,3	37,6	12,0	8,5	422

  SO4		374,0	374,0	374,0	374,0	5,4	3,8	11,5

 HCO3						34,2	35,1	95,8

   F		1,7	1,76	1,74	1,84	no det.		

 H3BO3		2.42	2.29	2.00	2.17	1,2	**	52,4

 H4SiO4 ð	190,0	194,0	192,0	192,0	57,6	45,0	208,0

  pH		3,28	3,25	3,22	3,20	7,2	7,05	9,45


notes: water samples from the lake (1- surface, 2- bottom) and in the new crater (3- surface, 4- bottom) taken in May 1996, 5- water from the lake (09.10.85), 6 - (19.06.85), 7- (20.08.93); In samples 1- 4 Fe2+ concentration was less than 0.5 mg/l, and in the other samples none was detected. (n.d. - not detected, d.l. - detection limit)

The lake became one of the largest reservoirs of acid water in the world. The general salt content in the lake water increased significantly. We calculated the change in overall salt reserves in the lake, using data on water composition before and after the eruption (table 2).

Table 2. Total reserve of chemical elements in the water of Karymsky Lake before 

and after the eruption (in tons).


Year    Ñl     SO4    HCO3    Na     K     Ca     Mg   Al    Fe    Mn    Zn    Cu

1993  11228   2530    11598  7380   442   3163   316   0.1   1.17  0.3  2.32   0.01

1996  24460   216730  no     40910  8350  38412  8381  3232  5629  992  32.6   26.8



The underwater eruption in the Academia Nauk Caldera Jan.2-3, 1996 was a unique event, seen by specialists for the first time. As a result of this natural event, the hydrological regime of the lake, along with its composition, changed completely. This can be classified as a natural ecological catastrophe. The results of the first year’s investigations into the consequences of the eruption allow us to construct the long-term evolution process of the lake back to its original state.


We would like to think Ya.D. Muravyev, V.I. Andreev, I.A. Markov for taking regular samples, as well as monitoring the temperature and level in the lake.
Our work was supported by the Russian Government Committee on Science and Technology, the Russian Fund for Fundamental Research, and the INTAS fund (project 94-3129).


Fazlullin S.M., Shuvalov R.A., Karpov G.A., Ushakov S.V. Subaqueous Eruption from Karymsky Lake (Kamchatka) and its Effects //Crater Lakes, Terrestrial Degassing and Hyper- acid Fluids in the Environment. Chapman Conference. Abstracts. September 4-9, 1996 Crater Lake, Oregon. 1996. P. 15.
Fedotov, S.A. The simultaneous eruption of two volcanoes on Kamchatka in January 1996. «Zemlya i vselennya». 1996. N3. P.60-65. (in Russian)
Karpov G.A., Muraviev Ya.D., Shuvalov R.A., Fazlullin S.M., Chebrov V.N. More details about the early January eruption //Bulletin of Global Volkanism Network. 1996. V 21. N 3. P. 9-10.
Karpov G.A., Muraviev Ya.D., Shuvalov R.A., Fazlullin S.M., Chebrov V.N. A subaqueous eruption from the caldera of Akademii Nauk volcano on January 2-3 1996 //Newsletter of the IAVCEI Commission on Volcanic Lakes. 1996. N9. P.14-17.