POAS VOLCANO - BUBBLING CAULDRON

Poas Volcano is a short drive "up the hill" from Pura Vida hotel - we are 31km from the summit at 2708 meters or 8,884 feet. There are only a few places in the world where you can drive up close to the edge of an active volcanic crater, and Poas National Park is one of them.

There are two craters you can visit (under normal circumstances) - the largest is nearly 1.5 km wide. Poas has been described as "a scene from Dante's Inferno". When the park is open, sulfuric gasses puff from vents 300 meters below the observation platform. Surrounding the smaller cone is a dense forested area that is one of the few remaining habitats of the scarlet macaw. During heightened volcanic activity the park may be closed. Poas is a stratovolcano with several eroded calderas, cones, and two crater lakes at or near its summit. Poas has erupted at least 39 times since 1828 and is in state of nearly continuous mild activity. Most of the eruptions are phreatic, caused by the interaction of lava and the water in the crater lake. Explosions vary in strength. Some explosions eject material about 1,500 feet (500 m) above the lake. The lake (and steam) is very acidic, with a pH of close to zero. Temperatures as high as 185 F (85 C) have been measured at the crater lake.

The news items were culled from local news reports each day including Observatorio Vulcanológico y Sismológico de Costa Rica (OVSICORI-UNA), La Nacion, AM Costa Rica (a local electronic news sheet) and Gallo Pinto (an electronic message board). The photos were mostly taken bu us from the hotel or at or on the road to the summit

THE ROAD TO POAS:

"The road to Poas from Pura Vida"

Drive 31 KM up passing a beautiful coffee growing area until you reach higher elevations known for their flower growing and beautiful mountain strawberries.

As you drive past rustic villages and mountain lanes shaded by trees you will move through diferent climate zones until you reach the summit - sometimes chilly so long pants and a jacket (rain gear in the wet season) are usually needed.

"Gustavo's Coffee Shop - friend to the birds"

Poas needs to be visited first thing when the gates open at 8am if possible as clouds invariably will come in later in the day making viewing impossible. But make sure you stop and "smell the roses" at Gustavo's Colibri Cafe. There's a free tasting of his special coffee blend if you remember to ask. A delightful little place.

RECENT EVENTS - 2006 ERUPTIONS:
March 24th - Volcan Poas Awoke
After 12 years of relative inaction surprised scientists, local residents and tourists with two eruptions. The first eruption was at 12:05 pm when a column of water and sediment was blown some 40 meters into the air.

"Costa Rica in 1861" - a string of volcanoes

The second eruption occurred at 7:53 pm and contained ash and solid material that rose some 200 meters (600 feet) in height, as reported by the Comisión Nacional de Atención de Emergencias (CNE)." The volcano which overlooks the city of Alajuela and can be seen from most of Pura Vida is being evaluated by scientists. Poas summit was closed that day but all other areas are open. This photo was from before this recent activity.

March 25th - Five New Eruptions
Bad weather complicated scientists investigating just what is currently occurring inside the volcano as the colossus launched rocks from the crater. The new eruptions began at 6:50 am, but no material has been ejected outside the current crater.

March 26th - Experts Analyzing Poas Eruptions
Three more eruptions were registered yesterday in Poas volcano, located 35 kilometers to the northwest of San Jose, in the province of Alajuela. P oas entered this current period of activity on Friday after remaining calm for 12 years.

From the rim viewing area last year

According to Lidier Esquivel, jefe de Prevencion de la Comision Nacional de Emergencias (CNE), the eruptions occurred yesterday at 12:00 noon, 4:38 and 5:00 pm. Two of them were of medium intensity, but the second one at 4:38 pm blew a column of gas, water and sediments to a height of at least 150 meters. None of the eruptions has sent material beyond the main crater of the volcano, which is 1,000 meters in diameter and 350 meters in depth. "It worries us that with the eruptions the level of the water in the Crater Lake has diminished and there is an increase in the temperature of that water," said Juan Dobles, head of the Poas Volcano National Park.

(And from: http://www.una.ac.cr/ovsi/) Staff from OVSICORI-UNA visited the east side of the volcano to confirm material charged with water, blocks and sediments from the bottom of the lake. Impact craters were documented in one area ranging from 300 to 700m beyond the source point. Crater size range from some cm to 70cm while, blocks associated ranged from few cm to 50cms and they were scattered randomly in the visited area.

Although they did not reached the extracrater area. Fine and superfine sediments were also documented and collected for later analysis. The area visited showed a gray appeareance although the rainy conditions accumulated small ponds of such sediments in crevices and lower drainages.

Recent acid rain effect on umbrella plant at summit

Material collected is composed of preexistent solid material from the bottom of the lake heavily altered by the action of acid and hot conditions during the last 12 years. Some of the more friable samples consist of compacted sediments that have aggregated miscellaneous granulometries.

Up to Monday 27 the tremor disappeared to resume normal seismic activity.

March 27th - May Reopen With Limited Access
Volcán Poás will be under close watch for three more days as scientists try to figure out if activity since Friday is an indication of a much larger eruption yet to come. Officials also said they wanted to plan ways of protecting visitors to the Parque Nacional Volcán Poás when it is finally opened. They are talking about letting spectators enter in small, closely controlled groups and restricting access to some areas.

Dusk steam eruption from the Pura Vida Volcano Studio

The volcano crater gave out two more eruptions Monday, bringing the total near 15 since midday Friday. So far all of the eruptions have been confined inside the volcano crater. The crater gives off hot gases. Nearly 300,000 tourists visit the volcano and its crater overlook each year.

March 28th - May Reopen?
Volcán Poás blew what we believe to be a cloud of steam and ash around 6pm as dusk settled. A couple of photos of that event are at right taken from Pura Vida.

March 31st - Still Closed
Park officials are trying to open the park for small groups of 50 starting April 1st. Park access will be limited but plans are to allow access to the main rim. Botos lake and some of the walkways will remain closed.

Dark steam cloud at dusk March 28th, from Pura Vida

April 1st - Restricted Access at the "bubbling cauldron"
We took a ride to the park April 1st. 31km up the hill from the Pura Vida Hotel. Arrived at 8am along with a few early arrivals. Park is open - park guards handed out special instructions for viewing. 1 hour in the park, restricted access, 20 minutes at the rim, evacuation vehicles, ambulance and breathing equipment available.

We parked and walked up after chatting with a government official who was interested in our steam plume photos from a couple of days ago as such events can't be seen from the summit.

A brisk 10 minutes walk gets you to the rim passing the results of recent acid rain from the crater. The results are obvious on the fragile umbrella plants common to high elevations here along the easy path to the viewing area at the rim of the crater.

Bubbling, steaming crater from visitors view point April 1

The sight is nothing short of "awsome" however much that word has been abused of late. A constant shifting of steam from the hot acid lake, constant shifts and changes from the many fumaroles including some with interesting martian green surroundings. The formerly sky blue lake is now a steaming white and everyone is advised to be cautious.

We stayed tranfixed by the constantly changing vista and the inspiring forces of nature bubbling in and around the crater lake.

Poas debris patterns (from http://www.una.ac.cr/ovsi/)

Close up of fumarole

The cauldron overflows

The entire crater

The entire crater constantly changing

On the road back down from Poas to Pura Vida

Over 140 Volcanoes, 5 active (from USGS)