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Earth Explorer is an online source of news, expertise and applied knowledge for resource explorers and earth scientists. Sponsored by Geosoft.

News & Views

News Archive

November 10, 2015

AGU's First Ask Me Anything: Water Science and Management

AGU's first ever Reddit Ask Me Anything, features Dr. Alberto Montanari, editor in chief of Water Resources Research on 12 November, from 12:00-2:00 P.M. EST, via Reddit's r/science portal ...

November 5, 2015

Massive graphite discovery could be on the cards for NQ

Graphite is a mineral of immense potential and value - its purer forms sought out for use in mobile phone technologies and the batteries that power...

November 1, 2015

Australia's junior sector turns to crowdfunding

Australian junior miners have decided to battle the capital drought afflicting the sector by turning to the Internet to raise funds...

October 28, 2015

Saudi Arabia's mining sector to triple by 2030

Mining contribution to GDP to reach SR260 billion by 2030 and create more than 100,000 jobs for citizens ...

October 26, 2015

Grant enables pioneering research of vast river systems in Great Plains and Asia

It's hard to exaggerate the importance of rivers to sustaining life for animals and people...

October 16, 2015

INFOGRAPHIC: "Gold off to races?"

This week, gold made a significant technical breakthrough ...

October 15, 2015

BHP raising $6.5bn fresh sign of mining turnaround

The mining industry's big players are themselves slowly beginning to change tack...

October 7, 2015

Could rock formations along Alabama highways offer clues to climate change?

Making predictions about climate variability often means looking to the past to find trends...

October 2, 2015

Petrobras' pre-salt drilling confirms high quality oil potential in Carcará

The drilling of the third well in the Carcará area (Block BM-S-8) in the Santos Basin's ultra-deep waters...

October 1, 2015

Eni enters Mexico with the development of three oil fields offshore

Eni won with a 100% share a production sharing contract to appraise, develop and exploit the oil fields...

September 23, 2015

Frank Arnott Award honors exploration visionary

A new award named in honor of Frank Arnott, a visionary geophysicist from the United Kingdom, has been introduced to recognize innovation in visualizing and integrating exploration data.

September 21, 2015

300m-year-old volcanoes discovered near Mullingar

Geographically, Ireland is often likened to a saucer: upturned at its mountainous edges and flat...

September 17, 2015

True giants of mining: World's top 10 iron ore mines

The price of iron ore on Thursday turned positive amid new signs that China...

September 15, 2015

GIS and History: Using the Past to Inform the Present

Using the power of Geographic Information Systems to track trends in everything from...

June 26, 2015

Where Big Data Jobs Are In 2015 - Midyear Update

Professional, scientific and technical services, information (IT), and manufacturing are the three industries doing the most Big Data-related hiring as of June, 2015...

June 25, 2015

Coiled Tubing Drill Rig Modified for H Coil

Trials of a new Coiled Tubing Drill Rig are underway in Australia. These rigs use a continuous, flexible tube, rather than drill rods, for faster, safer drilling at just 50c per meter...

June 17, 2015

First gas production from L6-B in the Dutch North Sea

Wintershall is expanding its natural gas production in the Netherlands: the unmanned mini-platform L6-B has started to produce natural gas off the Dutch North Sea coast. The first so called "Minimum Facility”...

June 16, 2015

Worldwide water quality app hits the web

Former Copernicus Masters competition winner EOMAP has launched the first harmonised, high-resolution inland water quality monitoring service based on satellite data...

June 15, 2015

Results from hole AR-15-44b add substantial size to NexGen's rapidly developing Arrow zone

NexGen reported on assay results for angled hole AR-15-44b from the successful winter 2015 program at the Arrow zone on its 100% owned Rook I property, Athabasca Basin, Saskatchewan...

Was that a tsunami or a hurricane?

New research into overwash deposits is improving our predictive understanding of tsunamis and hurricane events to help inform coastal systems response.

by Graham Chandler on November 5, 2013 applied

Pilarczyk, at right, with McMaster University former graduate student Simon Donato searching for evidence of older tsunamis that have impacted the Omani coastline.  Ras al'Had Sabkah, Oman, Arabian Peninsula, February 2007. 

On November 28, 1945, a subduction zone earthquake measuring 8.1 on the Richter scale occurred off the Makran Coast of what is now Pakistan. The resulting tsunami struck not only Pakistan but Iran, India and Oman with wave heights ranging from 2 to 13 metres. More than 4,000 people were killed, making it the second-deadliest tsunami ever to have occurred in the Indian Ocean – exceeded only by the Indonesian event of December 26, 2004, which killed upwards of 280,000.

Understanding such past disasters can go a long way toward predicting comparable ones in the future. Problem is, researchers lack sufficient eyewitness accounts and the body of geological evidence is small.

Fortunately attempts to analyze overwash deposits (the flow of water and sediment that does not return directly to its source) are proving helpful. This approach, which considers how storms, tsunamis and sea-level change have altered coastal systems, is the brainchild of Jessica Pilarczyk, who is currently doing post-doctoral research at the University of Pennsylvania’s Sea Level Research Lab.

[Click to enlarge]

Identifying and characterizing the 1945 Makran tsunami in Sur Lagoon, Oman.  Particle Size Distribution (PSD) plots created in Geosoft Oasis were used to detect subtle differences between tsunami overwash and normal lagoon sediments.  Species of foraminifera, along with their test (shell) size and condition, support particle size findings and provide additional insight into the source of sediment (e.g., offshore).  (Source:  Pilarczyk, J.E., Reinhardt, E.G., 2012. Testing foraminiferal taphonomy as a tsunami indicator in a shallow arid system lagoon: Sur, Sultanate of Oman.  Marine Geology 295-298, 128-136.)  

[Click to enlarge]

A comparison between the 2011 Tohoku-oku and A.D. 869 Jogan tsunami desposits in Japan.  PSDs highlight key similarities (and differences) between the two tsunamis and reinforce that both were of similar magnitude; the 2011 Tohoku-oki tsunami, the largest tsunami ever recorded, in fact had a predecessor.  (Source:  Pilarczyk, J.E., Horton, B.P., Witter, R.C., Vane, C.H., Goff, J., Chagué-Goff, C., 2012. Sedimentary and foraminiferal evidence of the 2011 Tohoku-oki tsunami on the Sendai coastal plain, Japan. Sedimentary Geology 282, 78-89.)

Pilarczyk began by developing a method for detecting paleo-tsunamis using foraminifera (mircro-organisms) and mollusks and their taphonomic, or decay-related, characteristics. The latter include angularity, colour, size, fragmentation, and so on. It wasn’t long before the method proved successful in Sur Lagoon, Oman, which contains stratigraphic evidence of the 1945 Makran tsunami. Similar studies of overwash at Anegada in the British Virgin Islands are shedding light on tsunami threats in the eastern Caribbean islands.

A recent test involved sampling inland deposits from the 2011 Japanese tsunami and comparing them with underlying sediments deposited by an older event in the same area, namely the Jogan tsunami of AD 869. The methodology consisted of removing organics from the sediment samples, homogenizing them, and identifying foraminifera taxonomy and condition. Grain-size analyses were done using a laser-diffraction particle size analyzer. Then, grain-size values for all samples were converted to the Wentworth-Phi Scale, interpolated, gridded, and plotted as particle size distributions (PSDs) in Geosoft Oasis montaj.

“Using Oasis montaj provided the best way to effectively display detailed high-resolution particle size data,” says Pilarczyk. The software makes it possible to collapse hundreds of individual sediment profile graphs into one easy-to-interpret PSD plot, which in turn allows for the evaluation of subtle but important trends in the sediment record. “PSDs created in Geosoft Oasis montaj have enabled my research group to delineate previously undocumented tsunami deposits from Oman, the Caribbean, Japan, Sumatra, Chile, French Polynesia, and Alaska,” Pilarczyk notes.

In the Japanese test, researchers were able to discriminate between the tsunami deposit and the underlying soil because of the presence of recent and fossil foraminifera. There was also a pronounced change in grain size, which became finer upward and landward. Moreover, the PSDs showed the distinct separation of sand units deposited by both the 2011 and AD 869 tsunamis from the finer soils.

Pilarczyk and her research group are now assessing the risk of tsunamis to the Tokyo region by locating and interpreting geologic evidence of older events preserved along the coastline. “Anticipated outcomes of this are significant and include the first-ever geologic documentation of tsunamis impacting Tokyo,” she notes.

Scanning Electron Microscope (SEM) images of foraminifera indicating varying test (shell) condition.  Fossil and unaltered (e.g., no evidence of corrosion and abrasion) foraminifera are indicators of tsunami overwash.

Meanwhile in Indonesia, she is using the technique to map out modern foraminiferal distributions off northern Sumatra so that they can be compared to a series of overwash deposits found in a coastal cave. Similar research is under way in Chile and the South Pacific islands of Wallis and Futuna.

The technique is also of interest to climatologists. “Climate projection models are increasingly using geologic evidence of sea-level change and storm frequency to constrain their models and provide more accurate projections,” says Pilarczyk.







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