Arabia Weather - With the rise and fall of ocean waves, the sea floor is affected at depth, and seismic waves arise as a result. They are characterized by their enormous strength and wide spread, as their effect appears in seismographs in the form of a steady pulse, and this phenomenon has increased in strength in recent years.
In a recent study published in Nature Communications , Professor Richard Aster, who serves as chair of the Department of Geophysics at Colorado State University, and his colleagues tracked this remarkable increase around the world over the past four decades.
In an article published on The Conversation website, Dr. Richard pointed out that available global data, in addition to ocean seismic studies and the use of satellites at the regional level, show a continuous increase in wave energy, and this increase has coincided with rising global temperatures and changes in Storm pattern.
Global seismic monitoring devices and networks constantly record a wide range of seismic phenomena, whether natural or resulting from human activity. Among these phenomena, seismic background signals stand out, which is one of the most prominent phenomena spreading around the world, and which is caused by the continuous noise resulting from ocean waves, which leads to... To produce accurate seismic signals using ocean waves.
Secondary microseisms, which is the most active method, produce seismic signals with a period between about 8 and 14 seconds. When sets of ocean waves intersect in multiple directions, interference occurs that leads to a change in pressure on the sea floor. It is worth noting that this type of signal is not always present.
As for the second way in which ocean waves generate global seismic signals, it is called the “primary microseismic process” and occurs when transmitted ocean waves directly affect the sea floor through the forces of attraction and push and due to water movements quickly descending to depth in areas where the water depth is less than About 300 metres , these signals appear as a steady hum with a period of 14 to 20 seconds in seismic data.
In the recent study on primary microearthquakes, researchers analyzed the intensity of these historical earthquakes dating back to the late 1980s at 52 seismic stations around the world. The results showed that 41 of these stations (79%) recorded large and gradual increases in energy over the decades, indicating The analysis indicates that average ocean wave energy has increased at an average annual rate of 0.27% since the late 20th century. Since 2000, the average global increase in rate has increased by 0.35% per year.
The researchers noted that this increase was most pronounced in regions of the Southern Ocean, especially near the Antarctic Peninsula, and wave energy has intensified faster in the North Atlantic in recent decades than at historical levels.
According to the researchers, they indicated that the oceans have absorbed about 90% of the excess heat that has been linked to increased greenhouse gas emissions as a result of human activities in recent years, and this increase in energy can be converted into more impactful waves and stronger storms, and the researchers stress that their results constitute an additional warning. For coastal communities, where rising ocean waves may pound coastlines, destroying infrastructure and eroding land.
The effects of increasing wave energy increase; Due to the continuous rise in sea level, which is affected by climate changes and land subsidence. Researchers stress the importance of taking measures to mitigate the effects of climate change and enhance the resilience of coastal infrastructure, in addition to developing environmental protection strategies.
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