非火山による震動と低周波地震は群れをなす
David R Shelly1, Gregory C Beroza, Satoshi Ide
1Department of Geophysics, 397 Panama Mall, Stanford University, Stanford, California 94305-2215, USA. dshelly@pangea.stanford.edu
Nature
|March 16, 2007
まとめ
非火山の震動は,断層の近くの地震信号であり,多数の小規模な地震として説明されています. この発見は,震動とスロースリップの出来事が関連した現象であることを示唆し,断層プロセスと地震の危険性についての洞察を提供している.
科学分野:
- 地震学 地震学とは
- 地震科学 地震科学 地震科学
- プレート・テクトニクス (プレート・テクトニクス)
背景:
- 非火山の震えは,主要な断層とゆっくりと滑りやすい出来事に関連した微妙な地震信号です.
- 震動のメカニズムを理解することは,深い断層のプロセスと地震の危険性を理解するために不可欠です.
- 震動とアセイミック・スリップの関係性は,地震学における未解決の問題である.
研究 の 目的:
- 非火山による震動の根本的なメカニズムを調査する.
- 地震震動とスロースリップイベントの関係を見極めるため.
- 欠陥の根底にある根本的なプロセスを解明する.
主な方法:
- 日本シコク島の地震データ分析.
- 非火山による震えを地震の群れとして特徴づける.
- 個々の震動イベントの発生メカニズムとしてシール・フォールティングの識別.
主要な成果:
- シコク島の下の非火山地震は,多数の小さな低周波地震で構成されています.
- これらの地震は,潜水地域プレートインターフェースのスイヤー断層から発生します.
- 震動とスロースリップの現象は,同じ根本的なプロセスの異なる表現であるようです.
結論:
- 非火山による震えは,小さなシェアフォルトによる地震の連続としてモデル化することができます.
- この研究は,震えとゆっくりと滑る現象の統一された説明を提供します.
- この研究は,断層の行動と地震の危険性評価の理解を前進させる.
関連する概念動画
Travelling Waves
A wave is a disturbance that propagates from its source, repeating itself periodically, and is typically associated with simple harmonic motion. Mechanical waves are governed by Newton's laws and require a medium to travel. A medium is a substance in which a mechanical wave propagates, and the medium produces an elastic restoring force when it is deformed.
Water waves, sound waves, and seismic waves are some examples of mechanical waves. For water waves, the wave propagation medium is water;...
Water waves, sound waves, and seismic waves are some examples of mechanical waves. For water waves, the wave propagation medium is water;...
Kinetic and Potential Energy of a Wave
All forms of waves carry energy; this is directly visualized in nature. For instance, the waves of earthquakes are so intense that they can shake huge concrete buildings, causing them to fall. Loud sounds can damage nerve cells in the inner ear, causing permanent hearing loss. The waves of the oceans can erode beaches.
In mechanical waves, the amount of energy is related to their amplitude and frequency. In the context of the above examples, large-amplitude earthquakes produce large ground...
In mechanical waves, the amount of energy is related to their amplitude and frequency. In the context of the above examples, large-amplitude earthquakes produce large ground...
Modes of Standing Waves - I
A close look at earthquakes provides evidence for the conditions appropriate for resonance, standing waves, and constructive and destructive interference. A building may vibrate for several seconds with a driving frequency matching the building's natural frequency of vibration; this produces a resonance that results in one building collapsing while the neighboring buildings do not. Often, buildings of a certain height are devastated, while other taller buildings remain intact. This phenomenon...
Shock Waves
While deriving the Doppler formula for the observed frequency of a sound wave, it is assumed that the speed of sound in the medium is greater than the source's speed through it. When this condition is breached, a shock wave occurs.
When the source's speed approaches the speed of sound, constructive interference between successive wavefronts emitted by the source occurs immediately behind it. Initially, scientists believed that this constructive interference would result in such high pressures...
When the source's speed approaches the speed of sound, constructive interference between successive wavefronts emitted by the source occurs immediately behind it. Initially, scientists believed that this constructive interference would result in such high pressures...
Frequency of Spring-Mass System
One interesting characteristic of the simple harmonic motion (SHM) of an object attached to a spring is that the angular frequency, and the period and frequency of the motion, depend only on the mass and the force constant of the spring, and not on other factors such as the amplitude of the motion or initial conditions. We can use the equations of motion and Newton's second law to find the angular frequency, frequency, and period.
Consider a block on a spring on a frictionless surface. There...
Consider a block on a spring on a frictionless surface. There...
Fault Types
When analyzing a single line-to-ground fault from phase A to ground at a three-phase bus, it is important to consider the fault impedance. This impedance is zero for a bolted fault, equal to the arc impedance for an arcing fault, and represents the total fault impedance for a transmission-line insulator flashover. To derive sequence and phase currents, fault conditions are translated from the phase domain to the sequence domain.
For line-to-line faults occurring between phases B and C, the...
For line-to-line faults occurring between phases B and C, the...


