Imaggeo on Mondays: Fresh breakout in the lava fields

20 Oct

Fresh Breakout in the lava fields. (Credit: Kate Dobson via imaggeo.egu.eu)

Fresh Breakout in the lava fields. (Credit: Kate Dobson via imaggeo.egu.eu)

Kate Dobson was a volunteer at the Hawaii Volcano Observatory (HVO) in 2001/02 and revisited the stunning Big Island in 2006. During her holidays Kate ventured out to the coastal section of the Pu’uO’o lava flow field and captured this spectacular image of a fresh lava breakout.

The Pu‘u ‘Ō‘ō vent is in the East Rift Zone of Kīlauea Volcano and began erupting on January 3, 1983, and has continued to do so for more than 31 years, with the majority of lava flows advancing to the south. The original eruptions during the early 1980s were typically short lived and characterised by the eruption of viscous and slow moving a’a’ lava flows. However, in 1986 the eruption shifted to Kupaianaha, 3 km to the northeast of the original eruption site, and the eruption style changed significantly. A quiet, but continuous eruption of pahoehoe lava followed, snaking its way down the pali (steep costal slopes) and coastal plains to eventually reach the ocean. This extensive succession of lava flows damaged areas of Kapa’ahu village and closed the coastal highway.

The breakout pictured in our Imaggeo on Mondays image (taken more recently, in 2006 but probably resulting from similar to the activity described above) “is approximately 60cm and is sourced from an inflating basaltic flow which I photographed from a few metres away” explains Kate, “ I was about 300m inland from the ocean entry, and about 4 miles (800m elevation drop) from the source vent at Pui’u O’o.” The entry of the lava into the ocean creates spectacular columns of steam which attract numerous tourists. Whilst the HVO and the Hawaii Volcanoes National Park staff try hard to restrict viewing of the spectacular natural display, curiosity often gets the best of people as Kate describes “ I had just stopped three poorly equipped tourists (trainers, no water, no sunscreen) from blundering onto the active area a little further upstream and was heading back towards the ocean when the break out happened”.

Lava flow entering the sea on SE coast of Hawaii. Hawaii, Hawai (Credit: HVO,  U.S. Department of Interior, U.S. Geological Survey)

Lava flow entering the sea on SE coast of Hawaii. Hawaii, Hawai (Credit: HVO, U.S. Department of Interior, U.S. Geological Survey)

Since the onset of the volcanic activity at the Pu‘u ‘Ō‘ō vent the activity has waxed and waned and has presented an ongoing threat to the local communities on the Big Island of Hawaii. Towards the end of June of this year a new lava flow started to threaten the residential area of Kaohe Homesteads and Pāhoa town in Puna. Whilst not unprecedented, what is unusual about this particular lava flow is that rather than flowing towards the southeast, the lava flow is erupting towards the northeast. Given the current rate at which the flow is advancing, scientists of the HVO expect it to reach Pāhoa town by mid-November. In the 1930s, when a lava flow threatened the large town of Hilo on the eastern coast of the Island, the then director of the HVO, Thomas Jaggar, attempted to stop the threat posed by the lava flow by bombing it! The success of the enterprise was limited but Mauna Loa stopped erupting before any major damage was caused.

The known unknowns – the outstanding 49 questions in Earth Sciences (Part IV)

17 Oct

We are coming to the end of the known unknowns series and so far we have explored issues which mainly affect the inner workings of our planet. Today we’ll take a look at the surface expression of the geological processes which shape the Earth. Topography significantly affects our daily life and is formed via an interplay between primarily tectonics and climate, but it also affected by biological, mechanical and chemical processes at the Earth’s surface. We’ve  highlighted how advances in technology mean detailed study of previously inaccessible areas has now become possible, but that doesn’t mean there aren’t still plenty of questions left unanswered!

Earth’s landscape history and present environment

Drainage patterns in Yarlung Tsangpo River, China (Credit: NASA/GSFC/LaRC/JPL, MISR Team)

Drainage patterns in Yarlung Tsangpo River, China (Credit: NASA/GSFC/LaRC/JPL, MISR Team)

  • Can we use the increasing resolution of topographic and sedimentary data to derive past tectonic and climatic conditions? Will we ever know enough about the erosion and transport processes? Was also the stocasticity of meteorological and tectonic events relevant in the resulting landscape? And how much has life contributed to shape the Earth’s surface?
  • Can classical geomorphological concepts such as ‘peneplanation’ or ‘retrogressive erosion’ be understood quantitatively? Old mountain ranges such as the Appalachian or the Urals seem to retain relief for > 10^8 years, while fluvial valleys under the Antarctica are preserved under moving ice of kilometric thickness since the Neogene. What controls the time-scale of topographic decay? (Egholm, Nature, 2013)
  • What are the erosion and transport laws governing the evolution of the Earth’s Surface? (Willenbring et al., Geology, 2013) Rivers transport sediment particles that are at the same time the tools for erosion but also the shield protecting the bedrock. How important is this double role of sediment for the evolution of landscapes? (Sklar & Dietrich, Geology, 2011, tools and cover effect); (Cowie et al., Geology, 2008, a field example).
  • Can we predict sediment production and transport for hazard assessment and scientific purposes? (NAS SP report, 2010)
  • What do preserved 4D patterns of sediment flow tell us from the past of the Earth? Is it possible to quantitatively link past climatic and tectonic records to the present landforms? Is it possible to separate the signals of both processes? (e.g. Armitage et al., Nature Geosc, 2011).

    Smaller-scale patterns at the limit between river channels and hillslopes (Credit: Perron Group, MIT)

    Smaller-scale patterns at the limit
    between river channels and hillslopes (Credit: Perron Group, MIT)

  • Can we differentiate changes in the tectonic and climate regimes as recorded in sediment stratigraphy? Some think both signals are indeed distinguishable(Armitage et al., Nature Geosc, 2011). Others, (Jerolmack &Paola, GRL, 2010), argue that the dynamics intrinsic to the sediment transport system can be ‘noisy’ enough to drown out any signal of an external forcing.
  • Does surface erosion draw hot rock towards the Earth’s surface? Do tectonic folds grow preferentially where rivers cut down through them, causing them to look like up-turned boats with a deep transverse incision? (Simpson, Geology, 2004).
  • How resilient is the ocean to chemical perturbations? What caused the huge salt deposition in the Mediterranean known as the Messinian Salinity Crisis? Was the Mediterranean truly desiccated? What were the effects on climate and biology, and what can we learn from extreme salt giants like this? (e.g. Hsu, 1983; Clauzon et al., Geology, 1996; Krijgsman et al., Nature, 1999; Garcia-Castellanos & Villaseñor, Nature, 2011). Were the normal marine conditions truly reestablished by the largest flood documented on Earth, 5.3 million years ago? (Garcia-Castellanos et al., Nature, 2009).

The next post will be our final post in the series and we will list open questions on how climate has contributed to shape the surface of planet Earth, from its surface to the emergence of life and beyond.

Have you been enjoying the series so far? Let us know what you think in the comments section below, particularly if you think we’ve missed any fundamental questions.

By Laura Roberts Artal, EGU Communications Officer, based on the article previously posted on RetosTerricolas by Daniel Garcia-Castellanos, researcher at ICTJA-CSIC, Barcelona

EGU Awards and Medals 2015

14 Oct

x81a0617_egu_foto_pfluegl_140430.jpg__1280x99999_q85_subsampling-2Yesterday, the EGU announced the 35 recipients of next year’s Union Medals and Awards, Division Medals, and Division Outstanding Young Scientists Awards. The aim of the awards is to recognise the efforts of the awardees in furthering our understanding of the Earth, planetary and space sciences. The prizes will be handed out during the EGU 2015 General Assembly in Vienna on 12-17 April. Head over to the EGU website for the list of awardees.

Twelve out of the total 35 awards went to young scientists who are recognised for the excellence of their work in the early stages of their career. Eight of the awards were given at Division level but four young scientists were recognised at Union level, highlighting the quality of the research being carried out by the early career researcher community within the EGU.

As a student (be it at undergraduate, masters, or PhD level), at the EGU 2014 General Assembly, you might have entered the Outstanding Student Poster (OSP). A total of 49 poster contributions by young researchers were bestowed with a OSP award this year recognising the valuable and important work carried out by bugging geoscientists. Judges took into account not only the quality of the research presented in the posters, but also how the findings were communicated both on paper and by the presenters. Follow this link for a full list of awardees.

Further information regarding how to nominate a candidate for a medal and details on the selection of candidates can be found on the EGU webpages. For details of how to enter the OSP Award see the procedure for application, all of which takes place during the General Assembly, so it really couldn’t be easier to put yourself forward!

Imaggeo on Mondays: The perfect overnight stop.

13 Oct

Field camp at a cave. (Credit: Simon Virgo,via imaggeo.egu.eu)

Field camp at a cave. (Credit: Simon Virgo,via imaggeo.egu.eu)

Being an Earth scientist has its perks and camping overnight in a cave under an absolutely stunning unpolluted night sky has to be up there with one of the best! Our Imaggeo on Mondays image is brought to you by Simon Virgo who took the photograph in 2008 during an advanced mapping field course in structural geology in the Batain region of northeastern Oman.

The Batain region extends over an area of approximately 4000 km and is cross cut by a number of east-west trending wadis (valleys that remain dry except during times of heavy rainfall). The Batain Group, consisting of a number of sedimentary and volcanic formations, ranges from Permian to Maastichtian in age. Itis thought to have been deposited in the former ‘Batain Basin’ off eastern Oman and was later destroyed during compressional tectonics from the Group, consisting of a number of sedimentary and volcanic formations, ranges from Permian to Maastichtian in age (299 to 66 million years ago. It is thought to have been deposited in the former ‘Batain Basin’ off eastern Oman and was later destroyed during compressional tectonics during the Cretacous/Paleogene, some 66 million years ago ( boundary (Immenhauser et al.,1998).

ʺThe area is a fantastic playground for structural geologists; it is full of folds (the little cave at which we camped has formed in the hinge of a saddle), small scale faults and large thrust, occasionally associated with megabreccias that show a block size of several meters” explains Simon.

Batain Radiolarites. (Credit: Simon Virgo, via imaggeo.egu.eu)

Batain Radiolarites. (Credit: Simon Virgo, via imaggeo.egu.eu)

The rocks exposed in the region are mostly radiolarites, seen in the picture above, also taken by Simon. Radiolarites are silica rich, chert-like rocks, formed in shallow or deep waters, which mainly consist of the microscopic remains of radiolarians. The units pictured here are 4–20cm thick alternating beds of red and white cherts. The colouring of the red layers results from organic pigments in the units.

The area is not only geologically rich, explains Simon, “other sights include prehistoric tombs with artefacts scattered on top the hills, a fantastic coast with lots of marine and terrestrial wildlife” and let’s not forget absolutely magnificent unpolluted night sky.

 

Some related Literature:

Schreurs, G. and Immenhauser, A. (1999), West-northwest directed obduction of the Batain Group on the eastern Oman continental margin at the Cretaceous-Tertiary boundary, Tectonics, 18, doi: 10.1029/1998TC900020.

Immenhauser, A., et al. (1998), Stratigraphy, sedimentology and depositional environments of the Permian to uppermost Cretaceous Batain Group, eastern-Oman, Eclogae Geologicae Helvetiae, 91.2, 217-235.

DeWever and Baudin (1996). Palaeogeography of radiolarite and organic-rich deposits in Mesozoic Tethys, GR Geologische Rundschau, 85, 310-326.

Imaggeo is the EGU’s open access geosciences image repository. Photos uploaded to Imaggeo can be used by scientists, the press and the public provided the original author is credited. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. You can submit your photos here.

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