Fourth special report of the Hawaiian Volcano Observatory of the U.S. Geological Survey and the Hawaiian Volcano Research Association: Steam blast volcanic eruptions: A study of Mount Pelée in Martinique as type volcano

T. A. Jaggar

Home/Archive/USGS

USGS · 70232750

Fourth special report of the Hawaiian Volcano Observatory of the U.S. Geological Survey and the Hawaiian Volcano Research Association: Steam blast volcanic eruptions: A study of Mount Pelée in Martinique as type volcano

T. A. Jaggar

View original source ↗Read source document ↗Export metadata ↓

Abstract

The investigation is concerned with the author's expedition to Martinique and St. Vincent in 1902 and comparison of the experience of investigators and sufferers with that of others in so-called "explosive" eruptions. The Hawaiian mechanism is reviewed with special reference to rifts, underground water, intrusion furnace, wedge rupture, and lowering of magma. These features of structure are applied to Martinique, St. Vincent, Kilauea, Tarawera, Sakurajima, Katmai, Taal and Tomboro as a series of steam blasts old and new. The comparison is found to be applicable and the analogy with Hawaii considered as fundamentally magmatic for gas and basaltic slag, brings out the contrast that lies in steam eruptions. For all volcanoes they are believed features of ground water and of collapse. Ground water stimulates lava eruptions. The Pelée disaster at St. Pierre May 8, 1902, followed by a dacite dome with spines, which renewed activity in 1929, is examined for paroxysms of downblast. These are distinguished sharply from the Carib migratory upblasts along valley fissures which are not uncommon elsewhere. The valleys are on rifts recognized as deep fumaroles. The Ghyben-Herzberg laws of ground water are applicable. Geyser rhythm was followed by Pelée, Soufriére of St. Vincent, and Kilauea in their sequence of paroxysms. Structure sections are drawn to scale, and the structural reactions of intrusion, rifts, boiler, gas effervescence, heat, and timing are thus outlined. The bearing of this machinery on volcanism in general, on world ignisepta and on reaction of magma is suggested. It is contended that steamblast is a climax of eruption in the water zone and should be sharply delimited from the rising and intrusion of fundamental earth magma, and from the high pressure water reactions of ocean bottoms. Rising magma is considered an age-long elevatory force along volcanic lines, modified by cyclical yielding. Compared with oceanic volcanism continental irruption in sediments is a separate science in experimental field geophysics. Every locality supramarine or submarine of warm ground and steep thermal gradient is a subject for volcanology, if pulsating ground water is critically, thermally and chemically measured. Authors are referred to herein by names and dates in parentheses, as listed in the appendices.

Explore related subjects

Report of the Hawaiian Volcano Observatory Report

Source-reported bounding extent: 14.395443542701218° to 14.879096301785548° latitude; -61.230926513671875° to -60.81138610839844° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

T. A. Jaggar. 1949. Fourth special report of the Hawaiian Volcano Observatory of the U.S. Geological Survey and the Hawaiian Volcano Research Association: Steam blast volcanic eruptions: A study of Mount Pelée in Martinique as type volcano. https://pubs.usgs.gov/publication/70232750

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS1950

Fifth special report of the Hawaiian Volcano Observatory of the Hawaiian Volcano Research Association and the U.S. Geological Survey: Abrasion hardness

After reviewing the work of sclerometry, this paper shows that yielding and relative softness are the mechanical basis of what should be called malacometry. The experiments have been made with diamond drills, ring cuts, end millers and grinding wheels. Auerbach's "limited scope of the Mohs list" is quantitatively confirmed. The wear of diamonds is examined. A program is carried out, for rotary or annular abrasion by diamond under three applications of energy, each progressively slower. A selected commercial talc is the control substance of softness value 100. The instruments used are synchronous motors, drill presses, wheel grinders, and watchmaker lathes. Some 200 minerals, woods, metals, glasses and plastics were originally measured. Hardness tables and curves are shown for comparison with volumetric abradability. For a Mohs succession the softer substances abrade relatively more under higher energy of contact friction, and any one substance shows higher relative values under lower energy of attrition; in other words, under slower scratching. An artificially cut diamond octahedron gives more consistent results than a natural crystal, under light pressures. Standard successions of relative abradability measurements do not hold good under different energies of attack. Functions of plasticity, brittleness, cleavage, powder lubricity, ductility and the like introduce various anomalies, and constancy of pressure varies with variable yielding. The supposition that rhythmic instrumental abrading will hold its mechanical constants, while the substance attacked yields in accord with its own surface molecular mobility relative to a control substance, is only approximately true. At low energies the approximation is better than at high, but at high speeds the wear of tool is less. Hence the advantage of using with slow speed a replaceable tool. Substances of different categories such as steels and woods, differ in behavior from minerals. The Mohs System has the great advantage of extending the controls from mineral to mineral up through the whole scale, and is purely qualitative. It is not numerically quantitative at all in terms of equal units. A principal result of this investigation is that 80 per cent of the Mohs Scale, Numbers 3 to 10, are by common consent within 1 per cent of a malacometric scale numbered 1 to 100. The scientists who determined this relation were the sclerometry investigators of the nineteenth century, who mistakenly thought that the wide intervals of sclerometry are between the hard minerals. They used the reciprocals of the measures of yielding. The simple scratch tester finally arrived at is quite different from the instruments of Parts II and III. It eliminates diamond drilling, retains the Mohs controls and utilizes a dental grinding wheel and a modern low speed motor. The object of this research has been to design a simple instrument for many uses, especially for the mechanic's shop. It is planned for manufacture at an early date. The author is indebted to Dr. Earl Ingerson, Chief, Geochemistry and Petrology Branch, for critical correction and approval of this paper, by authority of the Director, U. S. Geological Survey.

Report of the Hawaiian Volcano Observatory↗

USGS1938

Third special report of the Hawaiian Volcano Observatory of Hawaii National Park and the Hawaiian Volcano Research Association: Ash formations of the island Hawaii

The purpose of the study was to determine the areal extent of the various volcanic ash formations, to describe them petrographically and to develop means of discriminating them. The ash formations, long known in a general way, had been only casually observed by geologists. Their interpretation and separation from other surficial materials has been much retarded by great differences in the degree of weathering and appearance of the same material in arid and in humid parts of the island. The wide distribution of ash formations in contrast to lava flows led to the hope that they could be discriminated and correlated and used as key horizons to work out the major events in the geologic history. It was believed that critical study of the effects of weathering on the ash formations, together with systematic tracing from regions of typical expression to others where the features were less typical and more obscure, would throw light on the stratigraphic relations and historical significance of the various units.

Hawaii↗

USGS1917

Second report of the Hawaiian Volcano Observatory of the Massachusetts Institute of Technology and the Hawaiian Volcano Research Association: On cyclical variations in eruption at Kilauea

This work treats chiefly of observed changes in the height of stand of molten lava in the crater of Kilauea. It also takes account of concurrent variations in the apparent energy of eruptive action at the surface of the magma column. With little doubt these conditions vary in a complex periodic way. To explain these periods in part an hypothesis is advanced which depends upon recurrent astronomical changes. It would be exceedingly difficult to develop this in any thorough dynamical way. Yet it is doubtful if any other treatment could serve quite adequately. Obviously the form given it in this study is crude. In ordinary language it is not easy to state the idea precisely, so as to differentiate the exact action hypothesized from action of a similar and familiar kind. Consequently such a presentation of the hypothesis as this is susceptible of erroneous comprehension. Besides, through incompleteness, this non-mathematical statement of it may be wrong in certain aspects or details. Therefore this paper must be read guardedly and with close attention.

Hawaii↗