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Samoan Islands' sinking dilemma

Some of the 2009 tsunami damage in Leone village
A tale of earthquakes, sea-level rise, and underestimated flood risk
Source: New Scientist

Pago Pago, AMERICAN SAMOA — In 2009, the serene beauty of the Samoan islands was violently disrupted by two magnitude-8 earthquakes, unleashing a devastating tsunami that claimed nearly 200 lives and inflicted extensive economic damage. Beyond the immediate tragedy, these seismic events triggered a less visible but equally insidious danger: the islands began sinking at an alarming rate. Recent studies reveal that this accelerated subsidence, combined with ongoing sea-level rise, substantially heightens the flood risk for these vulnerable communities — a risk that current models significantly underestimate.


The earthquakes of 2009 did more than shatter lives and landscapes; they altered the very foundation of the Samoan islands. As the Earth's crust rebounded from the released seismic stress, it set off a chain reaction deep beneath the surface. The Earth's mantle beneath the islands deformed, causing the land to sink more quickly than previously understood.

This geological shift is not merely a footnote in the islands' storied history; it is a ticking time bomb for future flood risk assessments. The current projections of sea-level rise, which fail to account for this accelerated subsidence, could leave the Samoan population woefully unprepared for the flooding that lies ahead.


At the heart of this issue is the stark reality that existing flood risk models do not incorporate the islands' enhanced sinking rate. This oversight is not just academic; it has real-world implications for the safety and sustainability of the communities that call these islands home. As sea levels continue to rise, the failure to adjust risk assessments accordingly could lead to inadequate preparation and mitigation strategies.

Without intervention, the residents of the Samoan islands face an uncertain future, one where the threat of flooding becomes an ever-present concern, eroding the very fabric of their daily lives and livelihoods.


The challenge now is to bridge the gap between scientific understanding and practical policy-making.

Acknowledging the accelerated sinking rate of the Samoan islands is the first step toward devising more accurate and effective flood risk models.

From there, the path forward involves a concerted effort among scientists, local authorities, and international partners to develop and implement strategies that bolster the islands' resilience against the dual threats of sinking and sea-level rise.

This endeavor will require not only technological and infrastructural innovation but also a deep commitment to the preservation and empowerment of the Samoan communities at the forefront of this environmental crisis.

The story of the Samoan islands is a poignant reminder of the complex interplay between natural disasters, geological phenomena, and human vulnerability. As the world grapples with the escalating challenges of climate change, the plight of these islands serves as a stark warning of what is at stake—and a call to action for a more informed, coordinated, and compassionate response to the environmental threats facing vulnerable populations around the globe.

James Dinneen is a science and environmental journalist from Colorado, based in New York. At New Scientist, he covers all things environmental, along with other curiosities.