Volcanic Ash : Rabaul Caldera, Papua New Guinea (Lauer, 1995)

Volcanic Ash : Rabaul Caldera, Papua New Guinea (Lauer, 1995)

Aerial view of Rabaul Town covered in volcanic ash, Papua New GuineaFollowing a 27-hour period of intense earthquake activity, Tavurvur and Vulcan volcanoes on opposite sides of the Rabaul caldera erupted on September 19, 1994, early in the morning. Nearby Rabaul Town (right, click for large-sized image) was covered with volcanic ash as thick as 1.5 m, and an estimated 90,000 people were displaced from the area.

"The volcanic ash was mushrooming out in thick clouds-but there was no noise. The earth had stopped moving. It was 6.15 am. We watched in awe. The clouds began to drift towards us... What a tremendous experience! But now the sky was darkening and black specks of ash were falling on us like light rain. There was also an overpowering small of sulphur."

7.30 am, after driving to a new location, about 8 km (5 mi) from Rabaul town. "Soon the clouds would reach Kulau too. Suddenly there were fears of being overcome by poisonous gas. The smell of sulphur was sickening and the air was a strange, yellowish colour. The the power went off. In a moment of panic, people, including our party which had now increased to eleven, decided to head for the safety of Kerevat, using the North Coast Road. Progress was extremely slow as the road was choked with half the population of Rabaul, all with the same idea. Eventually the vehicle traffic halted altogether. Due to unusual thermal patterns Kerevat was deluged by mud rain and the road quickly became impassable." The party returned to Kulua.

"The next day brought much of the same-but it seemed to drag on and on. The atmosphere was very heavy. There was no power. Every time we left the house we collected volcanic ash and pumice on our skin and in our hair. And the noise-the thunder and lightning was constant, with some almighty cracks. It was obvious that objects were being struck."

Five days later, describing a visit home to retrieve belongings: "There were parts of trees all over the road, flattened vegetation everywhere and everything covered in ash and mud. Our houseyard looked like a moonscape—house, water tanks, plants—all a drab grey. The trees along the bank had snapped and lost most of their foliage... inside the house was a depressing mess. The floors were covered in volcanic ash. There was even ash on the ceiling above the louvres and caked along the top of the curtains."

Nine days after the eruption: "The volcanic ash was dreadful all day yesterday. It was clearly visible in the air and I could feel and see it on my skin every time I stepped outside. I can't get used to wearing the mask and goggles. I found the smell of the masks nauseating so I've taken to wearing a folded handkerchief over my nose and mouth like a "baddie" in a Western movie."

AVolcanic Ash : Mount St. Helens, Washington

AVolcanic Ash : Mount St. Helens, Washington

"By noon, the City was engulfed in darkness by volcanic ash and communications by home telephone were impossible. It was like an eclipse of the sun that lingered, a blinding blizzard and an electrical storm all in one. Light-sensitive street lights came on automatically, traffic stopped, and a strange quiet fell on our community; and everywhere a talcum-like sandy gray powder kept accumulating. Cars, trucks, buses, and trains, all stopped, and planes were re-routed away from the ash cloud."

"From noon until 6:00 a.m. the following morning, the City was in total darkness. Three types of ash fell alternatively on the City: dark gray sand, medium gray sand, and a light gray cement-like dust. All three grades were gritty and light, difficult to sweep or shovel, especially when dry. To make matters worse, shifting winds blew the ash everywhere, severely impairing visibility and driving in our area. It was exceedingly harmful and abrasive to mechanical and electrical equipment, especially motors of vehicles, aircraft and electronic systems. Unlike snow, however, this "precipitation" was not going to melt!"

"The volcanic ash fall was especially crippling—Yakima received 5-8 cm (2-3 in) of this material in the first 24 hours following the explosion. We estimated that several million tons of volcanic ash was deposited on the entire region."