Volcano Anak, Krakatau

   Indonesia, May 2008 

M.Rietze, R.Roscoe

 

in deutsch


Krakatau is obviously one of the historically most interesting volcanoes due to the massive 1883 eruption .  The associated tsunamis and pyroclastic flows claimed well over 30000 lives.  Whilst the 19th century edifice was destroyed, three small islands remained flanking the site of the eruptive center.  In 1927, submarine eruptive activity commenced in the midst of these islands, marking the initial stages in the formation of Anak Krakatau (Child of Krakatau).  In late October 2007, Anak Krakatau once again burst into life.  Although we could not visit at the time and activity waned and stopped briefly in the following months, we kept an eye on the volcano.  In May 2008, renewed eruptive activity was evident and ash-clouds could regularly be seen on the webcam.  Hence, we (Martin and Richard) decided to visit the volcano quickly before activity could stop again.  Alain (Azimuth Travel) organized a fishing boat  and guides, both of which would stay with us for 4 nights at the islands.  After a smooth crossing and a brief cruise below the active crater where first strombolian eruptions could be observed we headed to Rakata island to set up base-camp.

      rr

The recent lava flows which descended from the main crater to the sea were unfortunately no longer active, however activity was still quite impressive.  Eruptions hurled smallish incandescent rocks to as high as 400mm above the crater.  Occasionally massive incandescent rocks the size of cars could be observed being thrown to just over the crater rim.  Some eruptions were accompanied by ash emission whereas others involved white gas clouds.  The volcano appeared to have alternating phases of different eruption styles which could last up to several hours.  The eruptions were often impressively loud and could be heard as well as felt.  The noise could be heard echoing back of the steep rock-face of Rakata.

   rr  

Hazy conditions hampered night-photography from Rakata beach, which would have otherwise provided a good perspective for viewing the new crater.  Further, the relatively calm waters infront of Rakata beach are a popular anchoring point for fishing boats.  We despaired several times when after setting up our tripods and aiming between the boats a new boat would turn up and park right in front of us.  This caused 3 changes of position during the first evening alone.

       mr

 Night shots from Rakata

 rr

The first full day of boat-based viewing was interesting with eruptions rarely more than 10 min apart and often in relatively quick succession from what appeared to be a number of vents.  On one occasion, rocks landed in the water near the boat, making the captain move to a safer position further offshore. 

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 Eruption throwing Rocks near boat

      mr

In the evening we were transfered by canoe from our “rocking boat” (often making framing really difficult) to a little rocky beach on the S side of Anak Krakatau.  Our boat then headed off to Rakata before dusk.  Many powerful eruptions could be experienced during the night and these peppered the flanks of Anak cone with incandescent material many times.  The initial plan to ascend the cone to look into the crater was quickly abandoned.

    rr   

   mr

Dread flash inside the eruption cloud. Here the electrostatic part is adopted by the friction of the ash particles. Simply the principle like in a thunderstorm, where rain / hail and wind are assembling an potential difference.

   mr

One incandescent bomb landed only 20m from our position (about 700m from the crater).  It could be seen approaching and must have been airborne for about 15 seconds.before it sizzled into the ground  The bomb had a diameter of maybe 40 cm after flattening on landing.  Sleeping would have been too dangerous and the volcano was too effective an alarm-clock anyway.

   rr   

The next morning we remained on land observing eruptions until the sun became too intense for comfort.  We then returned to the boat to cool off and then proceeded to our usual maritime viewing area below the crater.  Since the water is deep at this point anchoring is not possible and we drifted along the coast before occasionally returning to our starting position using the boats engine.

mr

A second night was then spent on Rakata beach.  Haze remained a problem and Richard ran faster than any time in the last 10 years when part of the rock-face of Rakata collapsed and rumbled to the ground just behind where he was sitting on the beach.

             rr                 mr   Rakata-Waran

On the third full day we cruised around to the SW coast of Rakata.  Here, the eroded deposits from the 1883 eruption can clearly be seen.  Later we again drifted under the crater watching the eruptions.  Some nice ash eruptions were observed and photographed if the camera was not pointing into the sea or the sky at the time as a result of the boats movement.

 rr

 Rakata eruption deposits

   mr

On the last night, Martin returned to Anak and tried a slightly different perspective while Richard returned to Rakata in the hope that it would be a clear night.  It turned out to be a wet and thundery night with poor visibility in the end.  Photography from Rakata was impossible but Martin managed to capture some of the again impressive eruptive action even though he had to pack his cameras away several times to keep them dry.

    mr

Rings of lava and smoke

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 Without doubts the most aesthetic colorful game were the leaving ash clouds out of the crater.

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Detailed photos are pointing out that the high ejected lava was still in a plastic texture

         mr 

mr        

At dawn, the camp on Rakata was dismantled and loaded onto the boat.  Martin was then picked up from Anak and after a leisurely breakfast we headed to the S tip of Rakata to do some snorkelling.  This was a nice cooling experience although loads of small jellyfish somewhat tempered the enjoyment.  In early afternoon we set off on the 3 hour trip to Carita on the N end of Java where we were to make an overnight stop before heading to Jakarta airport the next day.  Whilst the crossing was gentle, we bumped into a rock upon reaching the harbour.  This added a little excitement at the end of the trip.  However, no damage was done and we finally disembarked only 30min before a heavy thunderstorm arrived.

The trip was enjoyable yet the constant visibility problems make photography at Krakatau quite a problem.

For further photos and detailed background information on Krakatau, see

Photovolcanica.com  ALPE, images by M.Rietze

 

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© 2008 Photos und Text by M.Rietze (mr) and R.Roscoe(rr)

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