Abstract Recognizing that cyclical flexural fluctuations in sea ice sheets stimulated by waves can potentially initiate and perpetuate cracks that may ultimately lead to the destruction of an ice cover, we discuss some winter observations collected beneath the fast ice cover of Mordvinova Bay in the south-east of Sakhalin Island during 2018–2019 when a large crack formed that subsequently detached the offshore sea ice from the inshore ice plate by a wide lead. Energy density spectra show the ramifications of surface-gravity waves from the open ocean—primarily at swell frequencies—penetrating far into the ice from offshore, together with comparatively long, resonant leaky wave modes that gradually dissipate as they propagate alongshore but present a diminishing standing wave envelope of antinodes perpendicular to the coast. By evaluating amplitudes over different ranges of period, three swell wave events are assessed to determine whether they alone could have induced enough bending in the sea ice plate to cause breakage, acknowledging that this would normally occur much closer to the peripheral ice edge where the stresses are largest or as the swells run ashore. The foreshortened seaward standing curvature profile of leaky wave antinodes is also considered as a prospective source of cracking. Whilst neither pathway is found conclusively to be independently responsible for breaking the ice in this case, it is conjectured that the combined influence of swell and leaky waves acting together could cause the observed crack to form. In this case, fracture would occur at a distance of less than about four or so kilometres from the shore, where the antinodal curvatures induced by the standing leaky modes are sufficient. Conceding that the unrelenting flexing of the ice plate by waves and swell could affect the longevity of the sea ice as well, fatigue-precipitated weakening is explored. By determining the value of the mechanical stress at which an ensuing rupture of the fast ice could happen, it is shown that ice destruction can eventuate approximately 17 h after the swell first arrives at the ice edge from the Sea of Okhotsk, appreciating that breakup will depend on prevailing and prior meteorological conditions, the form and state of the sea ice including any preexisting defects, and the specific periods of swell waves that infiltrate the Mordvinova Bay ice sheet.

中文翻译：

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库页岛东南部莫德维诺瓦湾岸边快速海冰的裂缝形成和破裂

摘要 认识到波浪刺激的海冰盖的周期性弯曲波动可能会引发并延续可能最终导致冰盖破坏的裂缝，我们讨论了在东南部莫德维诺瓦湾快速冰盖下收集的一些冬季观测数据。 2018 年至 2019 年期间，库页岛发生了巨大的裂缝，随后形成了一条大裂缝，使近海海冰与近海冰板分开。能量密度谱显示了来自公海的表面重力波（主要是涌浪频率）从近海深入冰层的影响，以及相对较长的共振泄漏波模式，这些波模式随着它们沿海岸传播而逐渐消散，但呈现递减的驻留波腹的波包线垂直于海岸。通过评估不同周期范围内的振幅，评估了三个膨胀波事件，以确定它们是否单独会在海冰板中引起足够的弯曲以导致破裂，并承认这通常会发生在更接近应力的外围冰边缘最大或随着涌浪上岸。漏波波腹的缩短的向海站立曲率剖面也被认为是潜在的裂缝来源。虽然在这种情况下最终发现没有任何一条路径独立负责破冰，但据推测，膨胀和泄漏波共同作用的综合影响可能导致观察到的裂缝形成。在这种情况下，裂缝会发生在离岸边不到四公里左右的地方，其中由常设泄漏模式引起的波腹曲率是足够的。考虑到海浪和膨胀引起的冰板无情弯曲也会影响海冰的寿命，因此探索了疲劳导致的弱化。通过确定随后可能发生快速冰破裂的机械应力值，表明在膨胀从鄂霍次克海首次到达冰缘后大约 17 小时，冰破坏可能发生，意识到破裂将取决于当时的和先前的气象条件、海冰的形式和状态，包括任何预先存在的缺陷，以及渗入莫德维诺瓦湾冰盖的涌浪的特定时期。考虑到海浪和膨胀引起的冰板无情弯曲也会影响海冰的寿命，因此探索了疲劳导致的弱化。通过确定随后可能发生快速冰破裂的机械应力值，表明在膨胀从鄂霍次克海首次到达冰缘后大约 17 小时，冰破坏可能发生，意识到破裂将取决于当时的和先前的气象条件、海冰的形式和状态，包括任何预先存在的缺陷，以及渗入莫德维诺瓦湾冰盖的涌浪的特定时期。考虑到海浪和膨胀引起的冰板无情弯曲也会影响海冰的寿命，因此探索了疲劳导致的弱化。通过确定随后可能发生快速冰破裂的机械应力值，表明在膨胀从鄂霍次克海首次到达冰缘后大约 17 小时，冰破坏可能发生，意识到破裂将取决于当时的和先前的气象条件、海冰的形式和状态，包括任何预先存在的缺陷，以及渗入莫德维诺瓦湾冰盖的涌浪的特定时期。