Volcano news: Poás volcano, Costa Rica
Poas volcano (Costa Rica), activity summary Feb 2012: high-temperature fumarolic activity and sporadic small phreatic explosions
Tuesday Mar 13, 2012 11:05 AM | BY: T
High-temperature fumaraoles from the comosite cone (the "dome") at the shore of Poás' crater lake (photo: E. Fernández, 24 Feb 2012)During February, Poás activity consisted in strong high-temperature fumarolic activity and sporadic small phreatic explosions, reported by park rangers.
The latest monthly bulletin of Costa Rica's volcano observatory OBSICORI published a more detailed summary of Poás' activity during February summarized as follows:
The ultra-acid crater lake had a greenish-gray color with sporadic convection cells visible in the central part carrying sulfur in suspension. Lake temperature were measured at 44° C, which is a value significantly lower than those measured during most of 2009-2011. The pH value of the lake water was measured at 0.01, slightly "less" acidic than during November 2011 (pH -0.4).
The lake volume continued to decrease and its level dropped by 1.16 m between 25 Jan and 24 Feb. Concentrations of sulphate and chlorine increased.
The composite pyroclastic cone (the "dome") has high-temperature fumarolic activity and a strong emissions of blue gas (SO2). Fumarolic activity in the northwest sector of the "dome" had temperatures between 685 and 725°C. In the northern part of the "dome", temperatures were ranging between 640 and 727°C (at accessible points).
On the north wall and north of the "dome" at the shore, there are some underwater fumaroles which release a significant amount of sulfur particles. Temperatures in this area range between 74 and 90°C.
Links / Sources:
Links / Sources:
- Boletín de Vulcanología: Estado de los Volcanes Febrero 2012 (OVSICORI-UNA)
Wednesday, Jan 04, 2012
Fieldwork at Poás on 16 December showed new geyser activity from a vent on the N flank of the lava dome that formed in 2011. A water-and-mud fountain rose 5-6 m high, flowed into the lake, and built a terrace along the S shore. ... [more]
Saturday, Sep 24, 2011
Recently, a part of the lava dome inside the crater of Poas volcano has been showing areas of incandescence and flames of burning gas. ... [more]
Wednesday, Feb 10, 2010
Our correspondant from Costa Rica reports two phreatic eruptions from Poás volcano's crater lake on the morning of Feb 9. [more]
Friday, Jan 22, 2010
Our correspondant in Costa Rica reports a beautiful phreatic eruption at Poas volcano today at noon time. This is the second eruption (after the one on 25 Dec 09) in a short time span. [more]
Thursday, Sep 13, 2007
Laguna Caliente, the frequently visited summit lake of Poás volcano, exhibits signs that increased fumarolic activity is happening at the bottom of the lake: now greenish-gray in color, convection cells in the lake's center and dark gray floating particles are being noted.... [more]