火星の表面波と地殻構造
D Kim1,2, W B Banerdt3, S Ceylan1
1Institute of Geophysics, ETH Zürich, Zürich, Switzerland.
Science (New York, N.Y.)
|October 27, 2022
まとめ
火星の隕石の衝突による 表面波は 独特の地殻構造を明らかにしています 赤道二分法より北の地殻は インサイト着陸器より 密度が高く 変化が少ない.
科学分野:
- 惑星科学
- 地震学
- 地理学
背景:
- 火星の地殻の構造を理解することは その形成と進化の解読に不可欠です
- 火星での以前の地震研究は主にインサイト着陸機の下の領域に焦点を当てていました.
研究 の 目的:
- 地震波を用いて火星の地殻構造を調査する
- 切断波の速度の変化を判定し,密度や多孔性などの性質を推論する.
主な方法:
- 火星の2つの隕石の衝突によって発生した地表地震波の検出と分析.
- 衝突地点からインサイト着陸器までの経路に沿ったグループ速度分散の測定.
- 地震データの逆転により,様々な深さでのシェア波の速度構造が制限される.
主要な成果:
- 赤道二分法 (深さ5〜30km) の北にある火星の地殻におけるシェア波の速度は,最小の変動で約3.2km/sである.
- この地震速度は,インサイト着陸器の下の領域と比較して,より高い地殻密度またはより低い多孔性を示唆しています.
- インサイト探査機の下で見られる 層状の低速構造は 火星地殻の特徴ではありません
結論:
- 火星の地殻の構造は,特に赤道二分法とインサイト着陸場所の間で,重要な地域差異を示しています.
- これらの発見は,火星の地殻の厚さと形成のグローバルモデルに挑戦し,より空間的に多様な地震データの必要性を強調しています.
- 地震表面波分析は 火星や他の地上の構造を調査するための強力なツールを提供します.
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