MAGNETIC SURVEY OFF THE WEST COAST OF NORTH AMERICA, 32{degrees} N. LATITUDE TO 42{degrees} N. LATITUDE

摘要

A ship-towed magnetometer survey of an area 250–300 miles wide off the foot of the continental slope along the coast of California has revealed a narrow pattern of anomalies of about 400 gammas magnitude trending north-south for more than 500 miles. The pattern is interrupted at the known faults and elsewhere; offset of the pattern at the Murray fault suggests a right-lateral displacement of about 84 nautical miles. The anomalies are such as might be expected of slablike structures underlying the ocean floor; geological possibilities include basic lava flows, topography of the main crustal layer, and intrusion of ultrabasic material from the mantle.