Seismic rotation waves: basic elements of theory and recording

Returning to the old problem of observed rotation effects, we present the recording system and basic elements of the theory related to the rotation fi eld and its association with seismic waves. There can be many different causes leading to observed/recorded rotation effects; we can group them as follows: generation of micro-displacement motion due to asymmetry of source processes and/or due to interaction between seismic body/surface waves and medium structure; interaction between incident seismic waves and objects situated on the ground surface. New recording techniques and advanced theory of deformation in media with defects and internal (e.g., granular) structure make it possible to focus our attention on the fi rst group, related to microdisplacement motion recording, which includes both rotation and twist motions. Surface rotations and twists caused directly by the action of emerging seismic waves on some objects situated on the ground surface are considered here only in the historical aspects of the problem. We present some examples of experimental results related to recording of rotation and twist components at the Ojcow Observatory, Poland, and L'Aquila Observatory, Italy, and we discuss some prospects for further research

Density Field of Dislocations and Fold Deformation Problem

変形理論の2つの基本的量-変形テンソルと転位密度テンソルとは,それぞれ幾何学的相当量をもつている.しばしば幾何学的相当量を示すために,座標系を連続的媒質の実際の点と結びつける.このようにして,媒質の変形と同時に座標系の変形が起る

Gravity and low-frequency geodynamics

This fourth volume in the series Physics and Evolution of the Earth's Interior, provides a comprehensive review of the geophysical and geodetical aspects related to gravity and low-frequency geodynamics. Such aspects include the Earth's gravity field, geoid shape theory, and low-frequency phenomena like rotation, oscillations and tides.Global-scale phenomena are treated as a response to source excitation in spherical Earth models consisting of several shells: lithosphere, mantle, core and sometimes also the inner solid core. The effect of gravitation and rotation on the Earth's shape is ana

転位密度の場と褶曲変形の問題

変形理論の2つの基本的量-変形テンソルと転位密度テンソルとは,それぞれ幾何学的相当量をもつている.しばしば幾何学的相当量を示すために,座標系を連続的媒質の実際の点と結びつける.このようにして,媒質の変形と同時に座標系の変形が起る

Dislocation Flow Through a Layered Earth Structure

In the paper are discussed the boundary conditions for dislocation density current in the layered media. The assumption of dislocation flow brings, to some extent, an explanation of earthquake distribution along a hypocentral surface. The angle of the inclination which in Benioff's graphs suffers rapid change at about 300 km is in our case changing gradually according to respective changes of rigidity μ. The relative rate of stress accumulation could be calculated basing on shape of hypocentral plane.前報(震研彙報44 (1966), 153-165)で導入した連続的転位分布の理論を成層構造媒質に適用して,弾性定数の深さに対する変化が転位帯の発達の仕方にどのように反映するかを調らべた.基本型式がedge型である転位帯が地下深所から地表に向つてななめに伸びている場合を想定すると,その傾きは剛性率の高い深所において急であり,地表に向い剛性率が低下するにつれて緩やかになることが期待される.これは島孤地震帯において見られる探究浅発地震発生面の様相(第8図参照)と調和するように見える