| 释义 |
somma Physical Geogr.|ˈsɒmə|
Also Somma.
[a. It. (Monte) Somma, proper name of the feature of this kind associated with Vesuvius.]
A remnant of an older volcanic cone which partly or wholly encircles a younger cone; the rim of a caldera. Freq. attrib., as somma ring.
c1910H. R. Mill Dict. Geogr. Terms in L. D. Stamp Gloss. Geogr. Terms (1961) 426 Somma, originally, the rampart remaining from the old crater of Vesuvius and forming an arc around one side of the new one. The name is sometimes extended to similar formations in other volcanoes. 1917T. G. Bonney T. Anderson's Volcanic Studies 2nd Ser. vii. 39 This [ridge], according to Dr. Anderson, forms a Somma ring within which rises a smaller and a larger crater, both intermittently active. 1940Bull. Volcanologique VI. 217 The older volcanic mass on the eastern side may be a continuation of the Somma. 1944C. A. Cotton Volcanoes as Landscape Forms xi. 167 An example of a large cumulo-dome which has been built within a wide caldera or ‘Somma ring’ is the Soufrière of Guadeloupe, in the Lesser Antilles. 1975Fielder & Wilson Volcanoes of Earth, Moon & Mars vii. 88/1 The so-called somma-type of nested cone..is named after Mount Somma, a residual portion of the encircling volcanic rim unit which was the precursor of the present, centrally disposed, Vesuvius. 1979Nature 1 Nov. 24/1 It [sc. Soufrière volcano, St. Vincent] is a strato-volcano 1,220 m high with an open summit crater 1·6 km in diameter located in the southern part of a 2-km wide somma crater. |