Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Uplifted island

22.06.2015

The island Isla Santa María in the south of central Chile is the document of a complete seismic cycle.

Charles Darwin and his captain Robert Fitzroy witnessed the great earthquake of 1835 in south central Chile. Historical nautical charts from the „Beagle“-captain show an uplift of the island Isla Santa María of 2 to 3 meters after the earthquake.


Uplift in the Santa María island as a result of the Maule earthquake in 2010. The island experienced a sudden uplift about 2 meters during the earthquake. (Photo: M. Moreno, GFZ)

What Darwin and Fitzroy couldn’t know was the fact that 175 years later nearly at the same position such a strong earthquake would recur.

At the South American west coastline the Pacific Ocean floor moves under the South American continent. Resulting that through an in- and decrease of tension the earth’s crust along the whole continent from Tierra del Fuego to Peru broke alongside the entire distance in series of earthquakes within one and a half century. The earthquake of 1835 was the beginning of such a seismic cycle in this area.

After examining the results of the Maule earthquake in 2010 a team of geologists from Germany, Chile and the US for the first time were able to measure and simulate a complete seismic cycle at its vertical movement of the earth’s crust at this place.

In the current online-edition of „Nature Geoscience“ they report about the earthquakes: After the earthquake of 1835 with a magnitude of about 8,5 Isla Santa María was uplifted up to 3 m, subsided again about 1,5 m in the following 175 years, and upliftet anew 1,5-2 m caused by the Maule earthquake with a moment magnitude scale of 8,8.

The Maule earthquake belongs to the great earthquakes, which was fully recorded and therefore well documented by a modern network of space-geodetical and geophysical measuring systems on the ground. More difficult was the reconstruction of the processes in 1835.

But nautical charts from 1804 before the earthquake, from 1835 and 1886 as well as the precise documentation of captain Fitzroy allow in combination with present-day methods a sufficient accurate determination of the vertical movement of the earth’s crust along a complete seismic cycle.

At the beginning of such a cycle energy is stored by elastic deformation of the earth’s crust, then released at the time of the earthquake. “But interestingly, our observations hint at a variable subsidence rate during the seismic cycle” explains Marcos Moreno from GFZ German Research Centre for Geosciences, one of the co-authors.

“Between great earthquakes the plates beneath Isla Santa María are large locked, dragging the edge of the South American plate, and the island upon it, downward and eastward.” During the earthquakes, motion is suddenly reversed and the edge of the South America Plate and island are thrust upward and to the west.” This complex movement pattern could be perfectly confirmed by a numerical model. In total, over time arises a permanent vertical uplift of 10 to 20% of the complete uplift.

Records of earthquakes show that there are no periodically sequence repetition times or consistent repeating magnitudes of earthquakes. An important instrument for a better estimation of risks caused by earthquakes are the compilation and measurement of earth’s crust deformation through an entire seismic cycle.

Wesson, R. L., Melnick, D., Cisternas, M., Moreno, M. & Ely, L.: “Vertical deformation through a complete seismic cycle at Isla Santa María, Chile”, Nature Geoscience, Advance Online Publication, 22.06.2015, http://dx.doi.org/10/1038/ngeo2468  (2015). DOI: 10.1038/NGEO2468

For photos in printable resolution click here:
https://media.gfz-potsdam.de/gfz/wv/05_Medien_Kommunikation/Bildarchiv/Erdbeben%20in%20Chile/20150618_ISM_cover_2.jpeg

https://media.gfz-potsdam.de/gfz/wv/05_Medien_Kommunikation/Bildarchiv/Erdbeben%20in%20Chile/20150618_melnick_cover_3.jpeg

Franz Ossing
Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences
Deutsches GeoForschungsZentrum
- Head, Public Relations -
Telegrafenberg
14473 Potsdam / Germany
E-Mail: ossing@gfz-potsdam.de
Tel. +49 (0)331-288 1040
Fax +49 (0)331-288 1044
www.gfz-potsdam.de

Franz Ossing | Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>