Analysis of the Impact of Seabed Earthquakes on Coastal Structures and Foundation Design

Year : 2025 | Volume : 12 | Issue : 03 | Page : 42 49
    By

    Birendra Kumar Singh,

  1. Professor, Department of Civil Engineering, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, India

Abstract

Earthquakes in the seabed occur with varying magnitudes. Seabed earthquakes cause a rapid rise in water levels, which can lead to flooding and structural damage. Therefore, when designing buildings near the seashore, it is essential to account for the additional load on columns due to water thrust. Earthquakes occurring at the seabed generate intense ground acceleration of varying magnitudes, significantly affecting water levels and inducing destructive flooding along coastal regions. When seismic activity occurs beneath the ocean floor, the sudden displacement of rock strata results in the upward movement of large volumes of water. This process generates massive waves and abnormal water thrust that can severely damage structures near the shoreline. The additional hydraulic pressure acting on columns and foundations must therefore be considered in the design of coastal buildings, bridges, roads, and other civil infrastructure. During a high-magnitude earthquake, such as one measuring 9 on the Richter scale, ground acceleration can approach 0.9 g, creating substantial seismic forces within the seabed. These forces trigger rapid water level rise, sometimes exceeding 20 meters, and lead to high-velocity flows that exert both lateral and uplift pressures on structures. The combined effect of seismic force, hydrostatic thrust, and scouring action of floodwaters can undermine soil stability and erode supporting foundation bases. For structures located near seashores, foundation design must incorporate these additional loads. This includes accounting for increased bearing capacity requirements, providing sufficient depth to resist scouring, and employing reinforced concrete raft foundations with adequate projection and thickness to safeguard against soil erosion. The study highlights that failure to consider earthquake-induced seabed activity and associated water thrust may result in structural instability, collapse, or severe damage to lifeline infrastructure. Therefore, integrating seismic loading with hydrodynamic effects is essential to ensure the long-term safety and resilience of civil engineering projects in coastal regions.

Keywords: Seabed earthquake, water thrust, coastal structures, foundation design, hydrodynamic effects

[This article belongs to Journal of Offshore Structure and Technology ]

How to cite this article:
Birendra Kumar Singh. Analysis of the Impact of Seabed Earthquakes on Coastal Structures and Foundation Design. Journal of Offshore Structure and Technology. 2025; 12(03):42-49.
How to cite this URL:
Birendra Kumar Singh. Analysis of the Impact of Seabed Earthquakes on Coastal Structures and Foundation Design. Journal of Offshore Structure and Technology. 2025; 12(03):42-49. Available from: https://journals.stmjournals.com/joost/article=2025/view=234978


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Regular Issue Subscription Original Research
Volume 12
Issue 03
Received 24/09/2025
Accepted 03/10/2025
Published 04/10/2025
Publication Time 10 Days
116

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