足元の岩の重さで重力は僅かに変わる/en - 版の履歴

MamechiAdmin: 英語訳を取り込み（pages/translations_en.json）

2026-10-29T10:35:31Z

英語訳を取り込み（pages/translations_en.json）

← 古い版		2026年10月29日 (木) 19:35時点における版
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	{{豆知識		{{豆知識
	\|番号=0038		\|番号=0038
			\|投稿者=まめち編集部
	\|本文=Even at the same latitude and elevation, gravity is slightly stronger over dense rock or ore and weaker over thick sediments or cavities. Precise gravimeters can pick up the difference, so they are used in resource exploration and in surveying active faults.		\|本文=Even at the same latitude and elevation, gravity is slightly stronger over dense rock or ore and weaker over thick sediments or cavities. Precise gravimeters can pick up the difference, so they are used in resource exploration and in surveying active faults.
	\|なぜ=Gravity includes the pull of the rock beneath you, and denser rock is heavier for the same volume, so it pulls harder. Around Hudson Bay in Canada gravity is weaker than in the surrounding area, partly (roughly a quarter to a half) because crust pushed down by Ice Age ice has not yet fully rebounded.		\|なぜ=Gravity includes the pull of the rock beneath you, and denser rock is heavier for the same volume, so it pulls harder. Around Hudson Bay in Canada gravity is weaker than in the surrounding area, partly (roughly a quarter to a half) because crust pushed down by Ice Age ice has not yet fully rebounded.

MamechiAdmin: 英語訳の「更新が必要」の印を外す（訳は対応表と同じ）

2026-10-29T04:00:40Z

英語訳の「更新が必要」の印を外す（訳は対応表と同じ）

← 古い版		2026年10月29日 (木) 13:00時点における版
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	{{豆知識		{{豆知識
	\|番号=0038		\|番号=0038
	\|本文=~~<span class="mw-translate-fuzzy">~~Even at the same latitude and elevation, gravity is slightly stronger over dense rock or ore and weaker over thick sediments or cavities. Precise gravimeters can pick up the difference, so they are used in resource exploration and in surveying active faults.~~</span>~~		\|本文=Even at the same latitude and elevation, gravity is slightly stronger over dense rock or ore and weaker over thick sediments or cavities. Precise gravimeters can pick up the difference, so they are used in resource exploration and in surveying active faults.
	\|なぜ=Gravity includes the pull of the rock beneath you, and denser rock is heavier for the same volume, so it pulls harder. Around Hudson Bay in Canada gravity is weaker than in the surrounding area, partly (roughly a quarter to a half) because crust pushed down by Ice Age ice has not yet fully rebounded.		\|なぜ=Gravity includes the pull of the rock beneath you, and denser rock is heavier for the same volume, so it pulls harder. Around Hudson Bay in Canada gravity is weaker than in the surrounding area, partly (roughly a quarter to a half) because crust pushed down by Ice Age ice has not yet fully rebounded.
	\|ジャンル=科学・自然		\|ジャンル=科学・自然

MamechiAdmin: 英語訳を取り込み（pages/translations_en.json）

2026-10-29T03:58:33Z

英語訳を取り込み（pages/translations_en.json）

← 古い版		2026年10月29日 (木) 12:58時点における版
2行目:		2行目:
	{{豆知識		{{豆知識
	\|番号=0038		\|番号=0038
	\|本文=Even at the same latitude and elevation, gravity is slightly stronger over dense rock or ore and weaker over thick sediments or cavities. Precise gravimeters can pick up the difference, so they are used in resource exploration and in surveying active faults.		\|本文=<span class="mw-translate-fuzzy">Even at the same latitude and elevation, gravity is slightly stronger over dense rock or ore and weaker over thick sediments or cavities. Precise gravimeters can pick up the difference, so they are used in resource exploration and in surveying active faults.</span>
	\|なぜ=Gravity includes the pull of the rock beneath you, and denser rock is heavier for the same volume, so it pulls harder. Around Hudson Bay in Canada gravity is weaker than in the surrounding area, partly (roughly a quarter to a half) because crust pushed down by Ice Age ice has not yet fully rebounded.		\|なぜ=Gravity includes the pull of the rock beneath you, and denser rock is heavier for the same volume, so it pulls harder. Around Hudson Bay in Canada gravity is weaker than in the surrounding area, partly (roughly a quarter to a half) because crust pushed down by Ice Age ice has not yet fully rebounded.
	\|ジャンル=科学・自然		\|ジャンル=科学・自然

MamechiAdmin: 英語訳を取り込み（pages/translations_en.json）

2026-10-29T03:57:53Z

英語訳を取り込み（pages/translations_en.json）

← 古い版		2026年10月29日 (木) 12:57時点における版
2行目:		2行目:
	{{豆知識		{{豆知識
	\|番号=0038		\|番号=0038
	\|本文=Even at the same latitude and elevation, gravity is slightly stronger over dense rock or ore and weaker over thick sediments or cavities. Precise gravimeters can pick up the difference, so they are used in resource exploration and in surveying active faults. Around Hudson Bay in Canada gravity is weaker than in the surrounding area, ~~and part of this~~ (roughly a quarter to a half) ~~is attributed to~~ crust pushed down by Ice Age ice ~~that~~ has not yet fully rebounded.		\|本文=Even at the same latitude and elevation, gravity is slightly stronger over dense rock or ore and weaker over thick sediments or cavities. Precise gravimeters can pick up the difference, so they are used in resource exploration and in surveying active faults.
			\|なぜ=Gravity includes the pull of the rock beneath you, and denser rock is heavier for the same volume, so it pulls harder. Around Hudson Bay in Canada gravity is weaker than in the surrounding area, partly (roughly a quarter to a half) because crust pushed down by Ice Age ice has not yet fully rebounded.
	\|ジャンル=科学・自然		\|ジャンル=科学・自然
	\|ファクト度=A		\|ファクト度=A

MamechiAdmin: 英語訳を取り込み（pages/translations_en.json）

2026-10-29T03:03:47Z

英語訳を取り込み（pages/translations_en.json）

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<languages/>
{{豆知識
|番号=0038
|本文=Even at the same latitude and elevation, gravity is slightly stronger over dense rock or ore and weaker over thick sediments or cavities. Precise gravimeters can pick up the difference, so they are used in resource exploration and in surveying active faults. Around Hudson Bay in Canada gravity is weaker than in the surrounding area, and part of this (roughly a quarter to a half) is attributed to crust pushed down by Ice Age ice that has not yet fully rebounded.
|ジャンル=科学・自然
|ファクト度=A
|ファクト度の根拠=Confirmed with primary sources (GSI, AIST, abstracts of papers in Nature and Science). Not S because the Hudson Bay share differs between studies and the size of the gravity difference was not found in a primary source
|ネタ度=S
|ネタ度の根拠=Surprising that the weight of Ice Age ice still shows up in gravity today
|便利度=該当なし
|便利度の根拠=A fact worth knowing for its own sake
|検証ステータス=根拠あり
|根拠1URL=https://www.gsi.go.jp/buturisokuchi/grageo_gravity
|根拠1要約=Explanation by GSI. The size of gravity also changes with the density structure underground, and the results are used for resource exploration and estimating active faults
|根拠1格付け=一次
|根拠2URL=https://unit.aist.go.jp/igg/ja/services/img/s020701.pdf
|根拠2要約=AIST document "Seafloor gravity exploration". The denser the ground below, the stronger the surface gravity, and the less dense, the weaker. Gravimeters can detect changes of one hundred-millionth of surface gravity and are used for resource and active-fault surveys
|根拠2格付け=一次
|根拠3URL=https://ideas.repec.org/a/nat/nature/v390y1997i6659d10.1038_37339.html
|根拠3要約=Abstract of Simons and Hager (1997, Nature). About half of the Hudson Bay gravity anomaly is the result of incomplete post-glacial rebound
|根拠3格付け=一次
|根拠4URL=https://nora.nerc.ac.uk/id/eprint/19432/
|根拠4要約=Abstract of Tamisiea et al. (2007, Science). Models of glacial rebound that fit GRACE satellite data account for about 25 to 45% of the observed static gravity field over Hudson Bay
|根拠4格付け=一次
|補足=This is not a difference a bathroom scale can show; it takes a precise gravimeter. The rest of the Hudson Bay gravity low is thought to come mainly from mantle convection. Whether gravity is weaker over Japanese plains is not stated here because no solid source was found. The Hudson Bay gravity low is also in the Japanese Wikipedia article on Hudson Bay.
|検証日時=2026-10-29
|検証方式=AI＋人
|本家既出チェック=本家に既出
|本家の該当ページ=https://ja.wikipedia.org/wiki/ハドソン湾
|派生元=重力を測ると地下の様子や火山のマグマが分かる
}}