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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 III)

3 Oct

We continue exploring the biggest conundrums in Earth sciences in this third post of the known unknowns. In the two previous instalments of the series we’ve discovered what the major questions still to be answered about the early days of planet Earth and its inner workings are. We now move onto the planet’s surface. The advent of plate tectonic theory, arguably one of the biggest advancements in the geosciences of the past century, has allowed us to far better understand how continents are built and the hazards associated with moving plates. Nevertheless, there is still much we do not comprehend, opening the door for hugely exciting and innovative research opportunities.

Tectonic-plate motion and deformation

A cross section illustrating the main types of plate boundaries  (Image Source; WikimediaCommons; Author: Jose F. Vigil. USGS, http://pubs.usgs.gov/gip/earthq1/plate.html)

A cross section illustrating the main types of plate boundaries (Image Source: WikimediaCommons; Author: Jose F. Vigil. USGS, http://pubs.usgs.gov/gip/earthq1/plate.html)

  1. What is the relative importance of the forces driving plate tectonics: slab pull, slab suction, mantle drag, and ridge push? (e.g., Conrad & Lithgow-Bertelloni,JGR, 2004; Negredo et al., GRL, 2004, vs. van Benthem & Govers, JGR, 2010). What is the force balance and the geochemical cycle in subduction zones? (Emry et al., JGR, 2014) How much water (and how deep) penetrates into the mantle? (Ranero et al., Nature 2003) How much subcontinental erosion takes place under subduction areas? (Ranero et al.,Nature, 2000)
  2. What happens after the collision of two continents? Does continental collision diminish the rate of plate subduction, as suggested by the slab-pull paradigm? (Alvarez, EPSL, 2010)  How frequent are the processes of mantle delamination and slab break-off? What determines their occurrence? (Magni et al., GRL, 2013; Durezt & Gerya, Tectonoph., 2013)
  3. Why are orogens curved when seen from space? (Weil & Sussman, 2004, GSASP 383)
  4. How well do different approaches to establish plate motion compare? How does the long-term deformation derived from paleomagnetism and structural geology link quantitatively to the present-day motions derived from GPS and from neotectonic patterns of crustal deformation? (Calais et al., EPSL, 2003) How do these last two relate to each other? (Wang et al., Nature, 2012) Can we learn from regional structure of the crust/lithosphere from that link (or viceversa)?
  5. Are plate interiors moving in steady-state linear motion? How rigid are these and why/when did they deform? (Davis et al., Nature, 2005, and Wernicke & Davis, Seismological Research Letters, 2010).
  6. How is relative motion between continents accommodated in diffuse plate boundaries? (eg., the Iberian/African plate boundary). What determines the (a)seismicity of a plate contact?
  7. How/when does deformation propagate from the plate boundaries into plate interiors? (e.g., Cloetingh et al.,QSR, 2005)
  8. What is the rheological stratification of the lithosphere: like a jelly sandwich? Or rather like a creme brulée? (Burov & Watts, GSA Today, 2006). Is the lower crust ductile? Is strength concentrated at the uppermost mantle? Or just the other way around? (e.g., McKenzie et al., 2000, JGR; Jackson, GSA Today, Handy & Brun, EPSL, 2004; and a nice blog post).
  9. Does the climate-controlled erosion and surface transport of sediment modify the patterns of tectonic deformation? Does vigorous erosion cause localized deformation in the core of mountain belts and prevent the propagation of tectonic shortening into the undeformed forelands? Does the deposition of sediment on the flank of mountains stop the frontal advance of the orogen? Is there field evidence for these effects predicted from computer models? (Philip Allen’s blog) (Willett, JGR,1999,Whipple, Nature, 2009Garcia-Castellanos, EPSL, 2007)

    Earthquake damage to the Alexandia Square building in Napa, California (Image Source: Wikimedia Commons, Author: Jim Heaphy; User: Cullen328).

    Earthquake damage to the Alexandia Square building in Napa, California (Image Source: Wikimedia Commons, Author: Jim Heaphy; User: Cullen328).

  10. Can earthquakes be predicted? (Heki, 2011, GRLFreed, 2012, Nat.Geosc.). How far away can they be mechanically triggered? (Tibi et al., Nature, 2003). Little is known about how faults form and when do they reactivate, and even worse, there seems to be no clear pathway as to solve this problem in the near future. Unexpected breakthroughs needed.
  11. How can the prediction of volcanic eruptions be improved? What determines the rates of magma accumulation in the chamber and what mechanisms make magmas eruptible? See for example this article on the Yellowstone Caldera  and this paper regarding volcanic uplift.
  12. How much of the Earth’s surface topography is dynamically sustained by the flow in the mantle? In many regions, the elevation of the continents does not match the predictions from the classical principle of isostasy for the Earth’s outer rigid layer (the lithosphere). This deviation is known as dynamic topography, by opposition to isostatic topography. But what are the mechanisms responsible? Can we learn about the mantle dynamics by estimating dynamic topography? (Braun, Nature Geoscience, 2010). Can the hidden loads needed to explain the accumulation of sediment next to orogens (foreland basins) be linked to these dynamic forces? (Busby & Azor, 2012).
  13. How do land-forming processes react to climate change at a variety of scales, ranging from the Milankovitch cycles to the late Cenozoic cooling of the Earth? Is there a feedback from erosion into climate at these time scales, through the Carbon cycle and the weathering of silicates, for example? What is the role of the surface uplift and erosion of Tibet on the drawdown of atmospheric CO2 over the Cenozoic? (Garzione, Geology, 2008)

 

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!

In the second to last post in the series we will outline the top outstanding research questions with regards to the Earth’s surface: Earth’s landscape history and present environment.

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

GeoTalk: Matthew Agius on how online communication can help identify earthquake impact

8 Aug

In this edition of GeoTalk, we’re talking to Matthew Agius, a seismologist from the University of Malta and the Young Scientist Representative for the EGU’s Seismology Division. Matthew gave an enlightening talk during the EGU General Assembly on how communication on online platforms such as Facebook can help scientists assess the effect of earthquakes. Here he shares his findings and what wonders online data can reveal…

Before we get going, can you tell us a little about you’re area of research and what got you interested in using online communications to complement our understanding of earthquakes and their impact?

My area of research is the study of tectonic structures and dynamics using different seismic techniques. The regions I have studied the most are Tibet and the Central Mediterranean. During my student days many friends wondered about my research and I felt that there was a need to reach out for the public in order to eliminate misconceptions on how the Earth works, in particular about the seismic activity close to home – Malta. This led to the creation of a website with daily updates on the seismic activity in the Mediterranean. We set up an online questionnaire for people to report earthquake-related shaking. The questionnaire proved to be successful; hundreds of entries have been submitted following a number of earthquakes. This large dataset has valuable information because it gives an insight on the demographics in relation to earthquake hazard of the tiny nation.

How can social network sites such as Facebook and Twitter be used to assess the impact of earthquakes?

Nowadays the general public has access to smart phones connected to the internet, which have become readily available and affordable. This resulted in a rapid use of social websites. People increasingly tend to express themselves in ‘near’ real-time online. Furthermore, smartphones are equipped with various technologies such as a GPS receiver and an accelerometer – the basic set up of a seismic station – and also a camera. Altogether this has the potential to provide an unprecedented level of information about the local experience of an earthquake. Its immediate analysis can also supplement instrument-based estimates of early earthquake location and magnitude.

Out in the field – Matthew Aguis in the Grand Canyon. (Credit: Matthew Aguis)

Out in the field – Matthew Agius in the Grand Canyon. (Credit: Matthew Agius)

What sort of information can you gather from sites like Facebook or Twitter, and what can it tell you?

Users can post comments as well as photographs directly on a page, say a page dedicated to earthquakes. Such post are time stamped and can also have geolocation information. Although the posted information might seem too basic, the collective data from many users can be used to establish the local feeling in ‘real time’. Another way is to have a specific application that analyses the text expressed by social media users. Similar applications have already been considered in a number of regions such as USA and Italy, and have shown very interesting social sentiment expressed during and after an earthquake shake.

How do the earthquake sentiments relate to the geology? Can you see any patterns between what people say and share online and the intensity of the quake in a particular area?

This is a new area of research that is still being investigated. Earthquake intensity, shaking and damage in a local context, are known to vary from one place to another. These variations are primarily due to either the underlying geology, the seismic wave propagation complexities, or a combination of both. So far various mathematical models have been published for famous areas such as San Francisco Bay; soon scientists will have the opportunity to compare their models with information on people’s sentiment gathered in this new way. Such sentiment is expected to relate to the geology, to some extent.

And another shot of Matthew in the field – this time from Mount Etna. (Credit: Matthew Aguis)

And another shot of Matthew in the field – this time from Mount Etna. (Credit: Matthew Agius)

What are the difficulties of dealing with this sort of data, and how do you overcome them?

This type of data compilation is known as crowdsourcing. Although it is has powerful leads, one has to take careful measures on how to interpret the data. For example one must not assume that everyone has a public social profile on the internet where to posts his/her sentiment. One also has to consider that mobile phone coverage is sometimes limited to cities leaving out large, less inhabited areas without a network. Another limitation can be related to the list of specific keywords used during text analysis, a typical keyword could be ‘shake'; users might be using this term in a completely different context instead of when the ground is shaking! I think the best way to overcome such difficulties is to combine this data with current seismic monitoring systems; upon which an event is verified with the seismic data from across the investigated region.

During your talk you proposed other ideas for data analysis, how can it be used to support civil protection services and inform the public?

Until now social sentiment with regards to earthquakes has been studied through the use of Twitter or Facebook. But citizens are also making use of other online platforms such as news portals. All this information should ideally be retrieved and analysed in order to understand the earthquake sentiment of an area better. Furthermore, such studies must also be able to gather the sentiment in multiple languages and establish geolocation information from clues in the user’s text. I think it is time to implement a system to be used by civil protection services, whereby immediately after an earthquake has been established, an automatic alert is sent via a dedicated phone app and, at the same time, a web bot crawls the web to ‘read’ and analyse what people are expressing across multiple platforms. A felt map can then be generated in real time. This could be very useful for  civil protection services during a major disaster, helping them to redirect their salvage efforts as civilian phone calls become clogged.

Matthew also mans Seismoblog, a blog dedicated to the young seismologists of the European Geosciences Union – keep up with the latest seismology news and research on Seismoblog here.

Imaggeo on Mondays: Fuelling the clouds with fire

30 Jun

Wildfires frequently break out in the Californian summer. The grass is dry, the ground parched and a small spark can start a raging fire, but burning can begin even when water is about. Gabriele Stiller sets the scene for a blaze beside Mono Lake, exploring the events that got it going and what it may have started in the sky… 

While on shores of Mono Lake in the summer of 2012, I spotted something strange in the distance: a great blaze on the other side of the lake. We were on a trip through the southwestern states (a long tour through California, Nevada, Utah and Arizona). All the days before we had been continuously accompanied by thunderstorms that broke out during the afternoon. The photo was taken before the daily thunderstorm, and the large convective system already hinted to the next storm to come – and indeed it did, just a few hours later.

Desert fires close to Mono Lake, California. (Credit: Gabriele Stiller via imageo.egu.eu)

Desert fires close to Mono Lake, California. (Credit: Gabriele Stiller via imageo.egu.eu)

It was not clear if this convective cloud system was generated by uplift of heated air initiated by the fire, a process known as pyro-convection, or if it was simply a coincidence. After all, thunderstorms were a regular occurrence throughout our trip. This could have been the storm of the day, and the related convection could have transported the air and smoke from the fire upwards. Or a combination of both could have been behind it. The cumulus cloud was quite isolated, with clear sky surrounding it, but you can already see a small anvil developing (the area where ice is formed in the cloud) above the cauliflower-like cumulus – a hint towards a developing thunderstorm. Such a development would make the cloud into a cumulonimbus cloud.

So what caused the blaze? On 8 August 2012, the wildfire was started through lightning ignition by a thunderstorm coming from the Sierra Nevada, and it burned for several days on open grassland, far from human infrastructure. Due to these circumstances, firefighting was not particularly difficult for the authorities. However, more than 13000 acres were burned, and more than 500 people fought the fire. One of the priorities was to keep the amount of sage-grouse habitat burned to a minimum.

By Gabriele Stiller, Karlsruhe Institute of Technology, Karlsruhe, Germany

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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