volcano: May 2008 Archives

The UD Field Ecology students after walking the 1992 lava flow from Arenal.  Front row from left:  Katheryn Miller, Katherine Biernat, Noah Jouett, Lorea Ormazabal, Johanna Weston, Samantha Behrent.  Back row:  Adaire Chatry, Mary Boyum, Richard Marsden, Christopher Gurguis, Adriane Smith.

Volcan Arenal, by Jorge Barquero Hernandez (Lihssa San Jose, 2006) is the last of the volcano books that I shall be reviewing here. It is also the shortest at 50 pages, but contains the best photographs of Arenal of any of the books reviewed in this blog. It is available directly from the Arenal Volcano National Park (Parque Nacional Volcan Arenal).

The text is bilingual English/Spanish and documents Arenal's activity from 1968 to date.
The only shortcoming is that I would have preferred more text, but the photographs more than make up for this. Photographs include a rare pre-1968 photograph, as well as good coverage of the aftermath of the 1968 Vulcanian eruption, and various activity over the past 40 years. There are lots of good night-time photographs of incandescent lava and Strombolian activity. Also included are some excellent time-lapse stills of pyroclastic flows. These are amongst the best photographs that I've seen for portraying the speed and unpredictability of pyroclastic activity.

Volcanoes, by Peter Francis and Clive Oppenheimer (2nd Edition, Oxford University Press 2004) is probably the best volcano book currently in print. The late Peter Francis wrote the original first edition, which quickly became a classic when it was published in 1993. Clive Oppenheimer has done an admirable job of updating the text and covering more recent eruptions such as Soufriere Hills (Montserrat).

The target audience is definitely an educated audience, but a knowledge of geology is not necessary. Volcanology and igneous petrology both suffer from a lot of jargon, but Francis & Oppenheimer do a good job of concentrating on what is important. There are even some witticisms regarding the more obscure (but loudly argued) areas!

Coverage of Arenal is limited to a few sentences in the discussion of Vulcanian eruptions, and whether the bombs erupted in 1968 really were supersonic. Better coverage and photographs are provided for neighboring Poas which is noted for its phreatic eruptions. Despite these limitations for our study area, this book is strongly recommended for those who want a comprehensive and readable book about modern volcanology.

Active Lavas: Monitoring and Modelling, Edited by Christopher R.J. Kilburn & Giuseppe Luoungo; UCL Press 1993
This out of print book concerns the monitoring and modeling of lava flows with the intention of improving future monitoring and the protection of civilian populations.

As such it is is probably a bit specialized for our needs. However, of interest to us is Chapter 2, The blocky andesitic lava flows of Arenal volcano, Costa Rica (pp 25-72). This takes advantage of the almost-constant effusion of Arenal's lava flows over the preceding 15-20 years to study lava flows on all scales from individual flows up to an entire volcano.

The result is a very good description of the morphology and dynamics of Arenal's lava flows. Of particular note are the field observations of which could be easily mis-interpreted by a field geologist studying an ancient lava field. For example, striations of lava flow levees could be mis-interpreted as fault slickensides. Selective erosion, truncated lava flows, and accretionary levees are also analyzed.

There are some useful lava flow descriptions which I shall be using in my volcano presentation, but otherwise this book is for a technical (field geologist) audience.

The The Volcano Adventure Guide, by Rosaly Lopes (Cambridge University Press 2005) is intended for volcano visitors who want more than what the usual tourist guides can provide. As well as an introductory section on volcanism, chapters cover safety and planning a volcano trip. Most of the book covers a range of volcanoes that are (generally) readily accessible. Volcanoes are chosen according to notoriety, things to see (eg. an eruption in progress), and accessibility.

Regions covered are: Hawai'i; Continental USA; Italy; Greece; Iceland; Costa Rica; and the West Indies.

Volcano coverage includes history, maps, places to visit, and guidelines for repose (or in the case of Arenal, "bad weather"). Lopes also adds personal accounts which range from the human (1 million people living on the slopes of Vesuvius) through to her own potentially hazardous experience on Arenal.

The technical level is aimed at the interested lay reader. Gives a good sound coverage - much better than the average tourist guide, but does not get into technical details that might swamp most readers.

This is an excellent book for someone considering a visit to a volcano or two. It can be used to choose volcanoes to visit, and also to plan your actual visit. Of course volcanoes have a tendency to change, but the book should give you enough information so that you can find out the latest status before your planned visit.

The volcano of Chaiten in Chile abruptly woke up on 2nd May. I have yet to see any official analysis, but reports and photographs suggest a Plinian eruption is in progress. Some impressive photos can be found at Times Online and other newspaper sites. The Smithsonian pages for Chaiten have yet to be updated with news, but include some useful background.
Last eruption was about 9000 years ago. Caldera with rhyolite lava dome - famed as a source of obsidian in archaeological circles.

Chaiten is a long way from Costa Rica but both are home to subduction zone volcanism. Also, Plinian eruptions are relatively rare - there have probably been about half a dozen worldwide during my lifetime - so this is of note.

Regular reports of activity at Arenal are produced by the Observatorio Vulcanologico y Sismologico de Costa Rica - Universidad Nacional (OVSICORI-UNA). English language translations are usually published by the Smithsonian Global Volcanism Program roughly every month. The latest report is typical of recent activity from the past few months:

16 April-22 April 2008

In March, activity originating from Arenal's Crater C consisted of gas emissions, sporadic Strombolian eruptions, and occasional avalanches from lava-flow fronts that traveled down the SW flanks. Volcanic activity was at relatively low levels and few eruptions occurred. Acid rain and small amounts of ejected pyroclastic material affected the NE and SE flanks. Eruptions produced ash plumes that rose about 2.2 km (7,100 ft) asl. Small avalanches of volcanic material traveled down several ravines. Crater D showed only fumarolic activity.