SU1513408A1 - Method of seismic study of earthъs crust and mantle - Google Patents

Abstract

The invention relates to seismic exploration and is intended to study the crust and mantle using monotypic and exchange waves excited by earthquakes and explosions and recorded on systems of concentric circular and radial profiles. The purpose of the invention is to improve the accuracy of intelligence. The method describes calculation formulas for determining the step between observation points, concentric profiles, their radii and the number of radial profiles associated with the parameters of the medium and the waves recorded. 1 hp ff, 2 ill.

Description

The invention relates to seismic exploration and can be used to study the structure, velocity characteristics, anisotropy and other parameters of the earth's crust and mantle using three-component recording of monotypic and exchange waves from earth seals and / or explosions.

The aim of the invention is to improve the accuracy of studying the crust and mantle.

FIG. 1 is a profile layout diagram, top view; in fig. 2 - diagram of the course of seismic rays.

The drawing shows concentric 1 and radial 2 profiles, center 3 of the observation system, direction 4 of the approach of seismic waves, radius 5 of the environment study area 6, radius 7 of the observation system, distance 8 between adjacent circular profiles, seismic edges 9, exchange sites 10 , the displacement of 11 centers of the research area and the center of the observation system, the minimum 12 and maximum 13 demolitions of monotypic or exchange waves, the depth of 14 boundaries, the course of monotypic 15 and exchange 16 waves.

The method of seismic study of the crust and mantle is carried out as follows.

According to seismological studies of past years or reconnaissance seismological works, they are taken as to the observation points of the earthquake wave and / or explosions; on the one hand or different sides. Epicentral races are determined.

00

four

ABOUT

oo

315134.08

one hundred i and the corresponding exit angle i,

In the study area, where it is known from geological data what the maximum angles of inclination of the boundaries can be, the known radius determines the radius of the region of the total deep areas of the RO. RO ,,, is selected - the minimum of two radii

ten

R

0

n-Sc 2.21 ap / -Lp5,). j-Lp5) + 7nv n

og

de N - the depth of exploration is minimal,

vanities in a given interval of 20 depths 5 for our case

H and / - iifj

 The largest of the drift values of monotype or exchange waves, measured from the center (coordinates of the center HcI Uts) of the systems of the areas of common deep areas and defined as

L P -l | (Lx-Hz) +) 2; Ljs - | (Lp5ГХц) - (L „5-),

0

five

0

five

0

Ng N,

where. „„ „.LMVIH

L is the minimum and maximum seismic drifts for the lower and upper boundaries of the study area,

In the event that the waves approach the observation points from different sides, the values of R and L Rye are determined by the formulas

H, And,

f j LjyuSfJPl: lZ tlJM ,.

 , And, h,

 (L ddks, „d, +

WT

 - - ..eoccT min. East

2 (, ((, -),

t

where flg d

one

 min paD

T Mac.S. East

“JH. Vossg: maximum and minimum drifts of monotypic and (or) exchange waves, respectively, in the fall and rise of the upper boundary in the study area.

where Lp ,, Lpg, are the coordinates of the seismic Lpu, psy of the drift of the P or PS waves, determined from the observation point; b c is the error in constructing the boundary of a geological object or the error in measuring its physical parameters.

According to the geological assignment for the complex of geological and geophysical data, the radius of the study area RQ c and the values of H and H of the depths of the upper and lower interfaces is determined.

In the case of an unknown approach of the waves to the observation points (from one or different sides), the displacement of the center of installation 8 R and the distance between the circular profiles .uRup in shape are determined. -T

Ntn

O P LMIJ, H LMQKC

AND,

HI

 (Ky MIN

50

five

A system of observations is placed on the object of interest with the location of points at the intersections of circles and radial profiles and observations are made until at least three exchange waves are recorded from each geological object located in the study area.

The goal is achieved by simultaneous registration of longitudinal and exchange waves on circular and radial profiles x (at different azimuths of the wave approach), which allows to investigate local anomalies of the medium, such as velocity anisotropy, inclined exchange boundaries, etc.

Claims (3)

1. A method of seismic study of the Earth's crust and mantle using three-component registration of monotype and exchange waves at points located at the intersection of systems of circular concentric and radial profiles at distances determined so that regions with radii R o / LIN common deep sites monotypic and exchangeable waves excited by earthquakes and explosions, at least in contact between soba, rtl and. due to the fact that, in order to increase the accuracy of the study of the crust and mantle, according to the totality of geological and geophysical data, a three-dimensional study area with a radius K U | P -, V.Q,, the radius of the system of concentric profiles. determined by the formula R R , 15 where SR is the installation center offset relative to the center of the study area, depending on the magnitude of the seismic drift, the number of circular concentric profiles Nun. determined by the formula N cl R.JC. DKU where is lkue. the radial distance between adjacent circular concentric profiles, number of radial profiles N .. g read the formula f t H Rj 2R about mich. , 15134086 2. The method according to p. 1, about tl and h a yu and with the fact that when registering waves, approach n; on the one hand, Nt The terms SR and U Ry (. are determined by the formulas II Ht 8 K 1; lyn-G-lla1 s. 0 five go Lv S bur, KfЬ, .l. L n, minimum max tHi.   A1IN MIN And maximum seismic drifts for the lower (Hj) and upper (H,) boundaries of the study area. 3. The method according to claim 1, characterized in that when registering PRINCIPLES from different sides of the waves, S R and U R mules N, t R .b9f i: -i; i a "j-aa & .. determined by form5 ABOUT Ur, (L Hi n mox.pad min, TsAD .And, n,  - Moses. East ) +) fc 2 (L HI H, maize. missions ). H, T 1  ng min. 1ad MOKt-Boccr L.luu "-, maximum and minimum lpin. resurrected . monotypic and (or) exchange wave drift, respectively, in the fall and rise of the upper boundary in the study area. 13 7 / C and. 2