Tides, earthquakes, and volcanic eruptions

Dumont, Stéphanie; Custódio, Susana; Petrosino, Simona; Thomas, Amanda M.; Sottili, Gianluca

doi:10.1016/b978-0-323-90851-1.00008-x

Cited by 2 publications

(1 citation statement)

References 43 publications

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“…Laplace's paradigm can be summarized in two statements: (1) all masses on the surface or internal to a planet are set in motion by astronomical forces (particularly from the Sun, Moon, and Jovian planets) and (2) it is sufficient to know the polar motion or its time derivative (the lod) in order to have access to the periods of all moving masses on the Earth's surface or inside of it. This is why the revolution periods of planets (or their commensurate combinations) and luni-solar tides have been found in many observed time series of geophysical phenomena, ranging from hours to millions of years [1,2,5,7,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

On the Annual and Semi-Annual Components of Variations in Extent of Arctic and Antarctic Sea-Ice

et al. 2023

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In this paper, the 1978–2022 series of northern (NHSI) and southern (SHSI) hemisphere sea ice extent are submitted to singular spectral analysis (SSA). The trends are quasi-linear, decreasing for NHSI (by 58,300 km2/yr) and increasing for SHSI (by 15,400 km2/yr). The amplitude of annual variation in the Antarctic is double that in the Arctic. The semi-annual components are in quadrature. The first three oscillatory components of both NHSI and SHSI, at 1, 1/2, and 1/3 yr, account for more than 95% of the signal variance. The trends are respectively 21 (Antarctic) and 4 times (Arctic) less than the amplitudes of the annual components. We next analyze variations in pole position (PM for polar motion, coordinates m1, m2) and length of day (lod). Whereas the SSA of the lod is dominated by the same first three components as sea ice, the SSA of the PM contains only the 1-yr forced annual oscillation and the Chandler 1.2-yr component. The 1-yr component of NHSI is in phase with that of the lod and in phase opposition with m1, while the reverse holds for the 1-yr component of SHSI. The semi-annual component appears in the lod and not in m1. The annual and semi-annual components of NHSI and SHSI are much larger than the trends, leading us to hypothesize that a geophysical or astronomical forcing might be preferable to the generally accepted forcing factors. The lack of modulation of the largest (SHSI) forced component does suggest an alternate mechanism. In Laplace’s theory of gravitation, the torques exerted by the Moon, Sun, and planets play the leading role as the source of forcing (modulation), leading to changes in the inclination of the Earth’s rotation axis and transferring stresses to the Earth’s envelopes. Laplace assumes that all masses on and in the Earth are set in motion by astronomical forces; more than variations in eccentricity, it is variations in the inclination of the rotation axis that lead to the large annual components of melting and re-freezing of sea-ice.

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Section: Introductionmentioning

confidence: 99%

On the Annual and Semi-Annual Components of Variations in Extent of Arctic and Antarctic Sea-Ice

et al. 2023

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State transition matrix and Markov-chain diagram for frequent volcanic eruptions: Krakatoa, Indonesia

Harbowo,

Muliawati

2024

E3S Web of Conf.

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Krakatoa has been a global attraction throughout history. Historical records of eruptions on this volcanic island complex provide thrill and excitement for visitors at once. They are often stunned by sudden eruptions, noticed by columns of ash billowing high into the sky and drawing attention to the scene. However, eruptions such as this also risk visitors of an improper radius. Therefore, in this study, we aimed to reveal the probability pattern of eruptions to sustain preparedness for the worst. Through the Anakrakatau eruption dataset that we collected from 2018 to 2023 [n=540], we propose a transition matrix diagram of eruption events generated from probability analysis. The approach of this method is based on a Markov-chain analysis. This study assessed the period between eruptions and the probabilities of observed column height. In this study, state determination refers to the k-means clustering (k=3) each variable. The results show that there are states that represent the variety of circumstances transitions in frequent small activity eruption. The highest probability achieved at eruption with maximum ash column below 800 m and time gaps between eruptions in less than two days. The results of this study provide new insights into the probability of annual eruptions and provide information for sustainable risk mitigation purposes. This report can be a reference for visitors to the Krakatau area, either for education or research.

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Tides, earthquakes, and volcanic eruptions

Cited by 2 publications

References 43 publications

On the Annual and Semi-Annual Components of Variations in Extent of Arctic and Antarctic Sea-Ice

On the Annual and Semi-Annual Components of Variations in Extent of Arctic and Antarctic Sea-Ice

State transition matrix and Markov-chain diagram for frequent volcanic eruptions: Krakatoa, Indonesia

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