Volcano rule Beware of falling through unstable terrain
Falling on aa lava may be painful, but other types of volcanic terrain can be far more dangerous. Although ordinary pahoehoe lava is generally quite safe and easy to walk on, shelly pahoehoe is another matter. This type of lava is relatively common on Hawaiian volcanoes and is the subject of many scary stories told by volcanologists who have worked there. One of my colleagues' experience is a good example he was walking on a long-cooled lava flow on Mauna Loa, unaware that the lava underneath...
The different types of volcanic eruptions
The term volcanic eruption can describe a wide variety of phenomena, from the gentle oozings of lava that sometimes go on for years to the catastrophic explosions that are quickly over but which impact the region for many years to come. Volcanologists tend to sort different volcanic eruptions by their character this is a loose classification that reflects how explosive the eruptions are. It was pioneered by G. Mercalli, who is best known for his scale of seismic intensities. The classifications...
What makes a big bang
How much gas is dissolved in the magma and how easily it can come out are the key factors determining whether an eruption will be explosive or not. If the magma is viscous but also gas-poor it can erupt quietly as pasty lavas forming stubby flows tens of meters thick. Extrusion of these high-viscosity magmas is often likened to toothpaste being squeezed out of a tube and volcanologists sometimes use the expression toothpaste lava to refer to some of these flows. Sometimes the lava is pushed...
Hana Highway
Named the Highway to Heaven by tourism promoters, this famous road takes you halfway around the volcano along the northern and eastern coastline. It starts at the town of Kahului and ends at Kipahulu, at the mouth of the valley of the same name. Many visitors to Maui drive the Hana Highway and few forget the experience - 93 km 58 miles of narrow, windy, and sometimes single-lane road through tropical forest. It is best to take the drive at a leisurely pace and to arrange overnight lodgings at...
Midoceanic ridges
The volcanoes on our Volcanoes of the Atlantic tour are islands that have grown tall enough to poke out of the ocean's surface. These and the multitude of submarine volcanoes are born when magma rising along the Fig. 2.2. Sketch showing the Earth's mid-ocean ridges and subduction zones. Different types of volcanoes are formed over these tectonic zones. Modified from Scarth, 1994. mid-oceanic ridge creates new crust as it is erupted. Mid-oceanic ridges are zones where two tectonic plates are...
The volcano Tgn
Lassen Peak is the world's largest plug-dome - a volcano formed by viscous lava that erupts as an almost rigid piston, eventually plugging its own vent. Lassen Peak is the southernmost volcano in the Cascades Range, as well as its tallest non-stratocone, rising 610 m 2,000 feet above its surroundings and reaching an elevation of 3,187 m 10,457 feet . Before the eruption of Mt. St. Helens in 1980, Lassen held the honor of being the most recently active volcano in the continental USA. Although...
Tectonic setting
The Hawaiian islands are the world's best-known example of mid-ocean hot spot volcanism. The Mosaic of Landsat Multi Spectral Scanner MSS images of the Big Island of Hawaii. The caldera and rift zone of Mauna Loa are prominent in the southwestern part of the island. The blue-colored, relatively young flows from Kilauea can be seen in the southeast of the island. The older volcanoes are Hualalai located to the northwest of Mauna Loa, partly cloud-covered in this image , Mauna Kea north-central ,...
Hydromagmatic eruptions
This special type of volcanic eruption happens when large quantities of hot magma and water come into contact with each other, with explosive results. This interaction can take a variety of forms, including eruptions within crater lakes, under ice or snow, or eruptions in shallow water at sea. All these are somewhat alike Fig. 3.7. Sketch showing the islands of the Krakatau group before the eruption of 1883 A , after the eruption B and in 1960 C , showing Anak Krakatau which is still active...
Haleakala crater
The magnificent crater is the highlight of a visit to Maui. The steep, windy Haleakala Crater Road Hawaii 378 climbs up the western flank and is the only road leading to the summit. Watch out for cyclists - a Map of the Haleakala National Park showing the windy road to the summit, the local topography, and major trails and attractions. Modified from http www.haleakala.national-park.com, courtesy of Scott Rowland. Map of the Haleakala National Park showing the windy road to the summit, the local...
Mauna Loa Trail
Return trip to Mauna Loa Cabin 62 km 38 miles , elevation gain 2,008 m 6,588 feet , 14 to 16 hours. Return trip to summit 77 km 48 miles , elevation gain 2,291 m 7,515 feet , 20 to 22 hours. This is the most popular trail up Mauna Loa because it minimizes the possibility of altitude sickness. It was built in 1915 by the US Army, at the instigation of Jaggar, who wanted access to the volcano's summit eruptions. It is an easier trail than the Observatory's, but it is not for those in a hurry you...
Volcano rule Bring along safety equipment appropriate for the specific volcano
Rock climbers, mountaineers, and other outdoor-oriented people know the importance of safety equipment and wouldn't dream of leaving home without the appropriate gear. One of the problems with volcano equipment is that what is necessary will vary widely according to the type of volcano and the type of trip. A visit to the tourist spots of the Hawaii Volcanoes National Park requires no more than a sturdy pair of shoes, while a hike to the summit of Colima in Mexico calls for a gas mask, a...
Hawaiian eruptions
Hawaiian eruptions are, in general, the safest and most beautiful eruptions to watch. This type of activity takes its name from, of course, the Hawaiian volcanoes, but it happens all over the world. The magma erupted is high-temperature, low-viscosity basalt, with a low gas volatile content. In other words, the magma is a typical oceanic basalt. The resulting eruption is largely non-explosive and rates most often 0, sometimes 1, in the volcanic explosivity index. Such apparent mildness can...
A personal view A volcano for photographers
Lassen Volcanic National Park is perhaps the most pleasant of all the volcanic National Parks in the USA. It does not feel crowded or over-commercialized, even though it has numerous attractions. The Park is ideal for those who wish to hike, camp, and enjoy nature in an unspoiled setting, as well as learn about volcanoes. I find Lassen comparable to Crater Lake in beauty but far more varied in its volcanic attractions - and far more peaceful. There is no way of predicting how long the crowds...
Volcano photography
Volcanoes are one of nature's most rewarding subjects for photography. There are many books available that show beautiful volcanoes images and readers keen on photography should browse through them for ideas. These books, however, do not reveal how the photographer obtained the shots. A professional photographer could surely write a whole book on how to photograph volcanoes, but this has not yet been done. Hence I felt there was a need to include some general advice on volcano photography, even...
Sources of information on volcanic activity
Once you decide to visit a particular volcano, how do you find out about what its current level of activity is, plus all the other information that, for safety reasons, you should know about If the volcano is frequently visited by tourists and is monitored, this information will be easier to get than if the volcano is remote and seldom visited. However, a vast amount of information on volcanoes can be easily accessible by the non-specialist and this amount is only likely to increase in this age...
Tectonic setting 1
The American West is a complex volcanic region that spans not only a large geographical area but also a Tectonic setting of North America. The Juan de Fuca plate plunges underneath the North American plate. The boundary between the two plates is marked by a broad submarine mountain chain known as the Juan de Fuca Ridge. The ocean floor is spreading along the Ridge. Modified from Brantley, 1995. Active and potentially active volcanoes in the USA. Note that several of the Cascades volcanoes are...
Napau Crater Trail
Starting at the Mauna Ulu parking lot, this trail 16 km, 10 miles one-way provides close views of Mauna Ulu and plenty more. Try to do at least the first part of the trail 0.6 km, 1 mile that takes you on the northern side of Mauna Ulu and up Pu'u Huluhulu Shaggy Hill , a 60 m 200 feet high spatter cone about 400 years old. Near the foot of Pu'u Huluhulu, the trail crosses pahoehoe lava from Mauna Ulu, which has numerous tree molds. The hike to the top of Pu'u Huluhulu rewards you with...
Sliding Sands Trail to Halemauu Trailhead
Distance 21 km 13 miles elevation change 512 m, 1,680 feet downhill hiking time 7 to 8 hours. The famous Sliding Sands Trail starts by the Visitor Center parking lot. As you get to the crater rim, you can see the trail stretching along the crater wall and the immensity of Haleakala really becomes clear. The beginning of the trail goes over cinders from the Red Hill cinder cone, dating from the Kula period. It is worth stopping before the trail descends into the crater to get your bearings. To...