660 



EXPLORATION GEOPHYSICS 



TABLE 20 



APPROXIMATE RANGE OF VELOCITIES OF LONGITUDINAL 



WAVES FOR REPRESENTATIVE MATERIALS 



FOUND IN THE EARTH'S CRUST 



A. Classification According to Material 



Material 



Velocity* 



Ft./Sec. 



MJSec. 



Weathered surface material 1,000— 2,000 



Gravel, rubble, or sand (dry) 1,500— 3,000 



Sand (wet) 2,000— 6,000 



Clay 3,000— 9,000 



Water (depending on temperature and 



salt content) 4,700— 5,500 



Sea water 4,800— 5,000 



Sandstone 6,000—13,000 



Shale 9,000—14,000 



Chalk 6,000—13,000 



Limestone 7,000—20,000 



Salt 14,000—17,000 



Granite 15,000—19,000 



Metamorphic rocks 10,000—23,000 



Ice 12,050 



B. Classification According to Geologic Age 



Age 



Type of Rock 



Velocity 



FtJSec. 



MJSec. 



Quaternary Sediments (various degrees 



of consolidation) 1,000—7,500 



Tertiary Consolidated Sediments . . 5,000 — 14,000 



Mesozoic Consolidated Sediments . . 6,000 — 19,500 



Paleozoic Consolidated Sediments . . 6,500 — 19,500 



Archeozoic Various 12,500—23,000 



305— 2,290 



1,530— 4,270 



1,830— 5,950 



1,980— 5,950 



3,810— 7,020 



C. Classification According to Depth t 



0—2000 ft. 



(0—600 M.) 



Ft./Sec. 



2000—3000 ft. 



(600—900 M.) 



Ft./Sec. 



3000—4000 ft 



(900—1200 M.) 



Ft./Sec. 



Devonian 13,300 



Pennsylvanian 9,500 



Permian 8,500 



Cretaceous 7,400 



Eocene 7,100 



Pleistocene-to-Oligocene . 6,500 



13,400 



11,200 



10,000 



9,300 



9,000 



7,200 



13,500 

 11.700 



10.700 



10,100 



8,100 



* The higher values in a given range are usually obtained at depth, 

 t Data from B. B. Weatherby and L. Y. Faust, Bull. Amer. Assoc. Petrol. Geologists, 19 

 (1936) 1. 



