The 2004 Sumatra earthquake initiated one of the most devastating tsunamis of the modern age. Despite being a shallow underwater rupture, the following waves were recorded with massive heights. The surge of this tsunami destroyed approximately $10 billion of properties and took the lives of almost 230,000 individuals.
Researchers learned from this event that tsunamis are uncontrollable phenomena that manifest from even small-scale quakes beneath the grounds or water bodies. Since then, all warnings regarding the giant waves have been taken by communities seriously due to the effects it demonstrated on the affected areas.
Other public safety and awareness strategies were implemented across many countries, particularly in coastal regions prone to tsunamis.
Tsunamis Today
This picture, taken by a Miyako City official on March 11, 2011, and released on March 18, 2011, shows a tsunami breaching an embankment and flowing into the city of Miyako in Iwate prefecture shortly after a 9.0 magnitude earthquake hit the region of northern Japan. The official number of dead and missing after the devastating earthquake and tsunami that flattened Japan's northeast coast a week ago has topped 16,600, with 6,405 confirmed dead, announced on March 18, 2011.
Despite our efforts to keep people safe from tsunamis, experts are still clueless about how to predict these waves, especially those caused by earthquakes with small intensities.
Scholars from the University of Southern California developed a model that could explain the bizarre association between the severity of tsunamis and the space between continental shelves and underwater trenches called outer wedges.
Outer wedges are commonly the areas where tsunamis of various intensities emerge from. By studying these gaps, experts found an explanation that might help us predict how big an upcoming tsunami is, even if the tremor that triggered it is relatively small.
Through a database of recorded tsunamis from the past, the authors of the study were able to curate information about the seismic, bathymetric, geophysical, and global subduction zones that could assist us in determining the potential hazards brought by the gigantic waves.
In a press release, the USC Department of Earth Sciences specialist and lead author of the paper, Sylvain Barbot, explained that almost half of the global population resides in coastal regions. This alone risks communities and their infrastructures to damage earthquakes and earthquakes tsunamis could bring. But even if we can not stop these hazards, there are possible ways to mitigate their impacts, Barbot continued.
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Why Massive Tsunamis Occur After Small Earthquakes
These plans should be carried out by participating urban development groups to provide a safer place for medical and learning facilities. Moreover, there are various additions we could add to our preemptive solutions against the floods and the massive waves, such as describing the areas that might incur the most damage, and some of these are presented in the recent study, Barbot said.
The team discovered that large tsunamis materialize whenever a horizontal movement occurs and uplifts the sediment's outer wedge in areas right between trenches of deep water bodies and continental shelves.
The faults and folds of an outer wedge are responsible for diverting the horizontal motions caused by trench-breaking earthquakes into large-scale tsunamis, reports Science Daily.
Through the analysis of subduction zones, the team found that high-tsunami runups are likely to appear in Lesser Antilles, Cascadia, Hikurangi (New Zealand), and Western Makran (Iran). These future tsunamis are expected to reach heights measuring up to 160 to 300 feet, or about 50 to 90 meters.
The study was published in the journal Earth-Science Reviews, titled "Tsunami excitation in the outer wedge of global subduction zones."
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