Nav: Home

Precursors of a catastrophic collapse

May 16, 2019

On the morning of the 13th of March 1888, the inhabitants of the Finschhafen trading post on the east coast of New Guinea were awakened by a dull rumbling sound. An eyewitness later reported that the water in the port had receded at the same time. A short time later, several two- to three-metre high waves hit the coast. It was a tsunami on that fateful morning that devastated the surrounding coasts. Several thousand people probably died in New Guinea and the Bismarck Archipelago.

The cause of the tsunami was quickly discovered: the largest part of the volcanic island of Ritter Island, 150 kilometres from Finschhafen, had slipped into the sea in a single catastrophic collapse. However, some questions about the exact course of the landslide remained unanswered.

In the international journal Earth and Planetary Science Letters, researchers from the GEOMAR Helmholtz Centre for Ocean Research Kiel together with colleagues from the University of Birmingham, the University of Malta, the University of London and the German Research Centre for Geosciences, have now published a study showing that the volcanic slope of Ritter Island had already slipped before the catastrophe of 13 March 1888 - but much more slowly. "These new findings help us to better assess the hazard potential of other volcanic islands," says Dr Jens Karstens of GEOMAR, first author of the study.

The study is based on the expedition SO252 of the German research vessel SONNE to Ritter Island in Autumn 2016. With seismic methods, the international team led by Prof. Dr. Christian Berndt (GEOMAR) precisely measured the traces of the disaster of 1888. They found evidence that the flank of the island had moved sporadically over a long period of time before 1888. This is indicated by corresponding deformation of the subsurface at a smaller volcanic cone off the coast of Ritter Island.

It is unknown whether slow landslides at volcanic flanks are precursors of a catastrophic collapse, or even whether they might reduce the risk of such a collapse because they relieve tension from the volcanic system. "At Ritter Island, we now have evidence that sporadic, small landslides have preceded a much larger one," explains Dr Karstens.

Both types of landslides were observed last year on active volcanoes. Last year's eruption of Kilauea on Hawaii was accompanied by a landslide of the volcano flank, which caused a moderate earthquake. The eastern flank of Mount Etna in Sicily is also moving slowly towards the sea, as showed in a study published in Autumn 2018. In December 2018, an eruption of the volcano Anak Krakatau caused a landslide that triggered a tsunami in the Sunda Strait (Indonesia) and killed more than 400 people. The events at Anak Krakatau are comparable to those that took place on the 13th of March 1888 at the Ritter Island Volcano. This demonstrates the relevance of the findings at Ritter Island for hazard assessments on volcanic islands all over the world.

"The better we know the dynamics of such events, the better we can asses the hazard for a given region. Ritter Island is a very good case study because the volcano resembles many other volcanic islands and because the eruption and the tsunami are well documented thanks to eyewitness accounts. Together with our modern research methods, we can get a more complete picture of the processes of 1888," summarizes Dr. Karstens.
-end-


Helmholtz Centre for Ocean Research Kiel (GEOMAR)

Related Tsunami Articles:

Japanese slow earthquakes could shed light on tsunami generation
Understanding slow-slip earthquakes in subduction zone areas may help researchers understand large earthquakes and the creation of tsunamis, according to an international team of researchers that used data from instruments placed on the seafloor and in boreholes east of the Japanese coast.
New evidence reveals source of 1586 Sanriku, Japan tsunami
A team of researchers, led by Dr. Rhett Butler, geophysicist at the University of Hawai'i at Mānoa (UHM), re-examined historical evidence around the Pacific and discovered the origin of the tsunami that hit Sanriku, Japan in 1586 -- a mega-earthquake from the Aleutian Islands that broadly impacted the north Pacific.
Study models Tsunami Risk for Florida and Cuba
While the Caribbean is not thought to be at risk for tsunamis, a new study by researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science indicates that large submarine landslides on the slopes of the Great Bahama Bank have generated tsunamis in the past and could potentially again in the future.
'Space tsunami' causes the third Van Allen Belt
Earth's magnetosphere, the region of space dominated by Earth's magnetic field, protects our planet from the harsh battering of the solar wind.
Ancient tsunami evidence on Mars reveals life potential
The geologic shape of what were once shorelines through Mars' northern plains convinces scientists that two large meteorites -- hitting the planet millions of years apart -- triggered a pair of mega-tsunamis.
Preparations for a US west coast tsunami look to the past and future
Plans for managing tsunami risk on the West Coast are evolving, said scientists speaking at the Seismological Society of America's 2016 Annual Meeting, held April 20-22 in Reno, Nevada.
EARTH: Revealing potential tsunami inundation on California coast
Given new information about the capability of faults to produce stronger earthquakes than previously thought, researchers at the University of California Riverside wondered if the current tsunami hazard maps for California adequately predict inundation zones.
AGU: Better, faster tsunami warnings possible with GPS
Better, faster tsunami warnings are possible with GPS.
What would a tsunami in the Mediterranean look like?
A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean.
Study outlines impact of tsunami on the Columbia River
Engineers at Oregon State University have completed one of the most precise evaluations yet done about the impact of a major tsunami event on the Columbia River, what forces are most important in controlling water flow and what areas might be inundated.

Related Tsunami Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".