The Noto earthquake that occurred at 16:10 on January 1, 2024, now five days past, reveals the extent of the damage more clearly as the full picture emerges. This earthquake, named the ‘Reiwa 6 Noto Peninsula Earthquake,’ had a magnitude of 7.6 and a maximum seismic intensity of 7. However, it has been revealed that the ‘maximum acceleration,’ an indicator of the strength of the tremors, reached 2828 gal (gal is the unit of acceleration), comparable to the 2011 Great East Japan Earthquake. Over 1000 gal, a benchmark for a ‘major earthquake,’ was confirmed at seven locations throughout the Noto Peninsula. The Great East Japan Earthquake had a magnitude of 9.0, a maximum seismic intensity of 7 on the surface, and a maximum acceleration of 2933 gal, highlighting the significant scale of the Noto earthquake. For reference, magnitude (commonly denoted as M) indicates the scale of an earthquake, while seismic intensity reflects the strength of the tremors at various locations during the earthquake. Comparatively, the Great East Japan Earthquake’s magnitude of 9.0 ranks fourth globally, emphasizing its extraordinary size. The Hanshin-Awaji Earthquake had a magnitude of 7.3, making the Noto earthquake surpass it and become the second-largest earthquake after the Great East Japan Earthquake. Earthquake intensity is rated on a scale of 7 as the maximum, with six occurrences recorded since the establishment of the intensity scale in 1949, including the recent Noto earthquake.

2024年1月1日16時10分に起こった能登大地震は5日経った今、全容が分かればわかるほど被害の大きさが分かります。「令和６年能登半島地震」と命名された今回の地震は、マグニチュード7.6、最大震度7でしたが、揺れの強さの目安となる「最大加速度」が、２０１１年の東日本大震災に匹敵する２８２８ガル（ガルは加速度の単位）だったことが分かりました。「大地震」の尺度の一つとなる１０００ガル以上の観測点は能登半島各地の計７地点で確認されたそうです。東日本大震災はマグニチュードが9.0で、最大震度は地上部で7、最大加速度が2933ガルでしたから、今回の能登大地震がいかに大きなものかがわかります。因みに、マグニチュード（一般にMと表記）は、地震の規模を表す単位で、震度は、地震の際の各地点の揺れの強さを表します。マグニチュードで比べると、東日本大震災は9.0で、これは世界第4位ですからこれは桁外れ。阪神淡路大震災は7.3でしたから、能登大地震はこれを上回って、東日本大地震に次ぐ規模だった訳です。地震の震度は7が最高でこれ以上はなく、震度が定められた1949年以降では今回の能登大地震を含めて6つです。