The 2 February 1816 North Atlantic earthquake is virtually unknown to the international scientific community, and the few existing studies—solely based on two or three macroseismic intensities—pointed to a magnitude near 7 and a location at the eastern end of the Gloria fault in the Azores‐Gibraltar Fracture Zone (AGFZ). Through careful search, we discovered more than 40 independent macroseismic observations and were able to estimate a total of 26 values of intensity, covering a wide geographical area (Iberian Peninsula, Madeira, and Azores). To apply the Bakun and Wentworth (B&W) method to the macroseismic dataset, we also deduced intensity–distance attenuation equations for the three different Atlantic coasts. The B&W procedure enabled us to conclude that the 2 February 1816 earthquake had a moment magnitude of 8.6±0.3 at the 95% confidence level and an epicentral location of 37.8° N and 19.8° W, near the central part of the Gloria fault. These results place the event as the greatest known earthquake in the Gloria fault domain and as one of the greatest ever seismic events along the AGFZ, probably only surpassed by the 1755 Lisbon earthquake.

中文翻译：

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1816年2月2日，北大西洋M 8地震

国际科学界几乎不了解1816年2月2日的北大西洋地震，并且现有的研究很少（仅基于两到三个宏观地震烈度），指向的震级接近7，并且位于格洛里亚断裂东端。亚速尔群岛-直布罗陀断裂带（AGFZ）。通过仔细搜索，我们发现了40多个独立的宏观地震观测资料，并能够估算出总计26个强度值，覆盖了广阔的地理区域（伊比利亚半岛，马德拉群岛和亚速尔群岛）。为了将Bakun和Wentworth（B＆W）方法应用于宏观地震数据集，我们还推导了三个不同大西洋沿岸的强度-距离衰减方程。B＆W程序使我们能够得出结论，即1816年2月2日地震的矩震级为8.6±0。在格洛里亚断裂中央附近的95％置信水平和37.8°N和19.8°W的震中位置确定3。这些结果使该事件成为Gloria断层地区已知的最大地震，也是AGFZ上有史以来最大的地震事件之一，可能仅在1755年的里斯本地震中被超越。