地震ストラトグラフィーと地球のコア-マントルの境界地域の熱構造
R D van der Hilst1, M V de Hoop, P Wang
1Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge MA, USA. hilst@mit.edu
まとめ
この研究は,地震波分析を用いた地球深層構造を明らかにし,最も下層のマントルのインターフェースと温度変動を特定します. これらの発見は,地球に関する新しい洞察を提示します.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 地震学 地震学とは
- ミネラル物理学 ミネラル物理学
背景:
- 地球の深い内部 (D'') 領域は,コア-マントルの境界線のすぐ上にあるが,惑星の動力学において重要な役割を果たしている.
- マントルシリケートの熱力学的性質と相転移を理解することは,地震データを解釈する上で鍵となる.
研究 の 目的:
- 地震波分析を使用して高解像度で地球の深部 (D') を探査する.
- 構造的インターフェイスを特定し,D'層内の温度を推定します.
- ペロブスキートからポストペロブスキートへの相変化とその影響について調査する.
主な方法:
- 核に反射した切断波の3次元逆散射を用いた.
- 構造的な境界をマッピングするために地震波の速度を分析した.
- マントルシリケートの熱力学特性を活用して地震画像を解釈し,温度を推定した.
主要な成果:
- 中米と北米の下のD'層で,複数の断片的な連続的なインターフェースが検出されました.
- ペロフスキートからポストペロフスキートへの移行と一致する波速の広範な増加が観察されました.
- 核-マントルの境界温度を3950 +/- 200 Kで推定し,中米の下にある冷たいD'領域を特定した.
結論:
- 内部のD'層化は,複数の相境界の交差点を示唆している.
- 深い波速の減少は,ポストペロブスキートレンズを示唆する可能性があります.
- 推定の中核熱流は35〜160mW m(-2) の範囲で,世界の平均は50〜100mW m(-2) であることを示唆しています.
さらに関連する動画
06:55Kinematic History of a Salient-recess Junction Explored through a Combined Approach of Field Data and Analog Sandbox Modeling
Published on: August 5, 2016
07:58Data Processing Methods for 3D Seismic Imaging of Subsurface Volcanoes: Applications to the Tarim Flood Basalt
Published on: August 7, 2017
関連する概念動画
Temperature and Thermal Equilibrium
Heat and temperature are essential concepts for everyone every day. The study of heat and temperature is part of an area of physics known as thermodynamics. It is not always easy to distinguish heat and temperature.
The concept of temperature has evolved from the common concepts of hot and cold. The scientific definition of temperature explains more than just our sense of hot and cold. Temperature is operationally defined as the quantity measured with a thermometer. Furthermore, temperature is...
The concept of temperature has evolved from the common concepts of hot and cold. The scientific definition of temperature explains more than just our sense of hot and cold. Temperature is operationally defined as the quantity measured with a thermometer. Furthermore, temperature is...
Isothermal Processes
A thermodynamic process that occurs at constant temperature is called an isothermal process. Heat slowly flows into the system or out of the system to maintain thermal equilibrium. Processes involving phase changes like water evaporation into steam or freezing water into ice at a constant temperature are examples of Isothermal Processes.
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
Magnetostatic Boundary Conditions
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
Thermal Strain
Thermal strain is a concept that arises when we consider how temperature changes affect structures. Unlike the conventional assumption that structures remain constant under load, real-world scenarios often involve temperature fluctuations that can significantly impact these structures. Consider a homogeneous rod with a uniform cross-section resting freely on a flat horizontal surface. If the rod's temperature increases, the rod elongates. This elongation is proportional to the temperature...
Temperature Dependent Deformation
In a nonhomogeneous rod made up of steel and brass, restrained at both ends and subjected to a temperature change, several steps are involved in calculating the stress and compressive load. Due to the problem's static indeterminacy, one end support is disconnected, allowing the rod to experience the temperature change freely. Next, an unknown force is applied at the free end, triggering deformations in the rod's steel and brass portions. These deformations are then calculated and added together...
Thermodynamic Background
The law of mass action states that "the rate of a chemical reaction is directly proportional to the product of the molar concentrations of the reactants." It means that the more 'active mass' or 'concentration' of the reactants present, the faster the reaction will proceed.In a chemical reaction, there are forward and reverse reactions. The forward reaction is the process where the reactants combine to form products. The reverse reaction is the process where the products break down to form the...
