Open AccessMultiple Array Measurements of the P ‐wave Travel‐Time Derivative
Author(s) -
Corbishley Derek J.
Publication year - 1970
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1970.tb06737.x
Subject(s) - geology , travel time , geodesy , derivative (finance) , measure (data warehouse) , second derivative , geometry , surface (topology) , mathematics , seismology , mathematical analysis , database , transport engineering , computer science , financial economics , engineering , economics
Summary Data from four arrays have been combined to measure the slope of the P ‐wave travel‐time ( dT/dΔ ) curve of events occurring at distances Δ= 30°−104°. Multiple regression analysis was used and corrections, which are azimuthally dependent, estimated to correct for the near surface geology under the arrays. The method is suitable for estimating standard tables of the P ‐wave derivative. Anomalous features occur in the dT/dΔ curve at distances of 35–36, 48–49, 60, 68–70 and 84–85 degrees, corresponding to possible variations in the P ‐velocity gradient near the depths of 850–900, 1200, 1550, 1800–1900 and 2500 km. A comparison is made between these features and those found at similar distances by other studies.