First-of-its-Kind Study Reveals Surprising Ecological Effects of 2010 Chile EarthquakeMay 07, 2012
The reappearance of long-forgotten habitats and the resurgence of species unseen for years may not be among the expected effects of a natural disaster.
Yet that's exactly what researchers found in a study of the sandy beaches of south central Chile, after an 8.8-magnitude earthquake and devastating tsunami in 2010.
Their study also revealed a preview of the problems wrought by sea level rise--a major symptom of climate change.
In a scientific first, researchers from Southern University of Chile and the University of California, Santa Barbara (UCSB) were able to document the before-and-after ecological impacts of such cataclysmic occurrences.
A paper appearing today in the journal PLoS ONE details the surprising results of their study, pointing to the potential effects of natural disasters on sandy beaches worldwide.
The study is said to be the first-ever quantification of earthquake and tsunami effects on sandy beach ecosystems along a tectonically active coastal zone.
"So often you think of earthquakes as causing total devastation, and adding a tsunami on top of that is a major catastrophe for coastal ecosystems," said Jenny Dugan, a biologist at UCSB.
"As expected, we saw high mortality of intertidal life on beaches and rocky shores, but the ecological recovery at some of our sandy beach sites was remarkable.
"Plants are coming back in places where there haven't been plants, as far as we know, for a very long time. The earthquake created sandy beach habitat where it had been lost. This is not the initial ecological response you might expect from a major earthquake and tsunami."
Their findings owe a debt to serendipity.
The researchers were knee-deep in a study supported by FONDECYT in Chile and the U.S. National Science Foundation's (NSF) Santa Barbara Coastal Long-Term Ecological Research (LTER) site of how sandy beaches in Santa Barbara and south central Chile respond, ecologically, to man-made armoring such as seawalls and rocky revetments.
By late January, 2010, they had surveyed nine beaches in Chile.
The earthquake hit in February.
Recognizing a unique opportunity, the scientists changed gears and within days were back on the beaches to reassess their study sites in the catastrophe's aftermath.
They've returned many times since, documenting the ecological recovery and long-term effects of the earthquake and tsunami on these coastlines, in both natural and human-altered settings.
"It was fortunate that these scientists had a research program in the right place--and at the right time--to allow them to determine the responses of coastal species to natural catastrophic events," said David Garrison, program director for NSF's coastal and ocean LTER sites.
The magnitude and direction of land-level change resulting from the earthquake and exacerbated by the tsunami brought great effects, namely the drowning, widening and flattening of beaches.
The drowned beach areas suffered mortality of intertidal life; the widened beaches quickly saw the return of biota that had vanished due to the effects of coastal armoring.
"With the study in California and Chile, we knew that building coastal defense structures, such as seawalls, decreases beach area, and that a seawall results in the decline of intertidal diversity," said lead paper author Eduardo Jaramillo of the Universidad Austral de Chile.
"But after the earthquake, where significant continental uplift occurred, the beach area that had been lost due to coastal armoring has now been restored," said Jaramillo. "And the re-colonization of the mobile beach fauna was underway just weeks afterward."
The findings show that the interactions of extreme events with armored beaches can produce surprising ecological outcomes. They also suggest that landscape alteration, including armoring, can leave lasting footprints in coastal ecosystems.
"When someone builds a seawall, beach habitat is covered up with the wall itself, and over time sand is lost in front of the wall until the beach eventually drowns," said Dugan.
"The semi-dry and damp sand zones of the upper and mid-intertidal are lost first, leaving only the wet lower beach zones. This causes the beach to lose diversity, including birds, and to lose ecological function."
Sandy beaches represent about 80 percent of the open coastlines globally, said Jaramillo.
"Beaches are very good barriers against sea level rise. They're important for recreation--and for conservation."
The National Science Foundation (NSF)
Related Earthquake Current Events and Earthquake News Articles
Earthquake acoustics can indicate if a massive tsunami is imminent, Stanford researchers find
Stanford scientists have identified key acoustic characteristics of the 2011 Japan earthquake that indicated it would cause a large tsunami. The technique could be applied worldwide to create an early warning system for massive tsunamis.
'Caldas tear' resolves puzzling seismic activity beneath Colombia
Colombia sits atop a complex geological area where three tectonic plates are interacting, producing seismicity patterns that have puzzled seismologists for years.
New Explanation for Slow Earthquakes on San Andreas
New Zealand's geologic hazards agency reported this week an ongoing, "silent" earthquake that began in January is still going strong. Though it is releasing the energy equivalent of a 7.0 earthquake, New Zealanders can't feel it because its energy is being released over a long period of time, therefore slow, rather than a few short seconds.
How should geophysics contribute to disaster planning?
Earthquakes, tsunamis, and other natural disasters often showcase the worst in human suffering - especially when those disasters strike populations who live in rapidly growing communities in the developing world with poorly enforced or non-existent building codes.
GPS solution provides three-minute tsunami alerts
Researchers have shown that, by using global positioning systems (GPS) to measure ground deformation caused by a large underwater earthquake, they can provide accurate warning of the resulting tsunami in just a few minutes after the earthquake onset.
Penn Research Helps Paint Finer Picture of Massive 1700 Earthquake
In 1700, a massive earthquake struck the west coast of North America. Though it was powerful enough to cause a tsunami as far as Japan, a lack of local documentation has made studying this historic event challenging.
Western Indian Ocean earthquake and tsunami hazard potential greater than previously thought
Earthquakes similar in magnitude to the 2004 Sumatra earthquake could occur in an area beneath the Arabian Sea at the Makran subduction zone, according to recent research published in Geophysical Research Letters.
Using earthquake sensors to track endangered whales
The fin whale is the second-largest animal ever to live on Earth. It is also, paradoxically, one of the least understood. The animal's huge size and global range make its movements and behavior hard to study.
Helping to forecast earthquakes in Salt Lake Valley
Salt Lake Valley, home to the Salt Lake City segment of the Wasatch fault zone and the West Valley fault zone, has been the site of repeated surface-faulting earthquakes (of about magnitude 6.5 to 7).
Earth is 'Lazy' When Forming Faults Like Those Near San Andreas, Says UMass Amherst Researcher
Geoscientist Michele Cooke and colleagues at the University of Massachusetts Amherst take an uncommon, "Earth is lazy" approach to modeling fault development in the crust that is providing new insights into how faults grow.
More Earthquake Current Events and Earthquake News Articles