45 posts · 63,981 views
News and commentary from the wide world of Earth Science
Chris Rowan
44 posts
Anne Jefferson
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- October 20, 2011
- 12:39 AM
- 630 views
Does plate tectonics control magnetic reversals?
by Chris Rowan in Highly Allochthonous
Possibly, but this paper will not convince you. Continue reading →... Read more »
Pétrélis, F., Besse, J., & Valet, J. (2011) Plate tectonics may control geomagnetic reversal frequency. Geophysical Research Letters, 38(19). DOI: 10.1029/2011GL048784
- October 5, 2011
- 02:36 PM
- 614 views
Proof of earthquake triggering in Christchurch? Not so fast…
by Chris Rowan in Highly Allochthonous
When a magnitude 6.3 earthquake scored an almost direct hit on Christchurch in February, I discussed the possibility that rather than being a simple aftershock of... Read more »
Stramondo, S., Kyriakopoulos, C., Bignami, C., Chini, M., Melini, D., Moro, M., Picchiani, M., Saroli, M., & Boschi, E. (2011) Did the September 2010 (Darfield) earthquake trigger the February 2011 (Christchurch) event?. Scientific Reports. DOI: 10.1038/srep00098
- June 27, 2011
- 04:35 PM
- 1,167 views
Update: Christchurch aftershocks
by Chris Rowan in Highly Allochthonous
As the aftershocks of the Darfield quake continue, where do the future seismic dangers lie? Continue reading →... Read more »
Parsons, T., & Dreger, D. (2000) Static‐stress impact of the 1992 Landers earthquake sequence on nucleation and slip at the site of the 1999 M. Geophysical Research Letters, 27(13), 1949. DOI: 10.1029/1999GL011272
- June 24, 2011
- 01:18 PM
- 2,501 views
When a tree falls in a stream, there’s always something around to make use of it.
by Chris Rowan in Highly Allochthonous
Allochthonous may have some obscure usage related to rocks, but in ecology, allochthonous material is a major concept that underpins thinking about nutrient cycling and food web dynamics. In its most general definition, allochthonous material is something imported into an … Continue reading →... Read more »
Vannote, R., Minshall, G., Cummins, K., Sedell, J., & Cushing, C. (1980) The River Continuum Concept. Canadian Journal of Fisheries and Aquatic Sciences, 37(1), 130-137. DOI: 10.1139/f80-017
- May 27, 2011
- 01:12 PM
- 1,166 views
Bacteria in the sky, making it rain, snow, and hail
by Chris Rowan in Highly Allochthonous
Even though we all think of the freezing point of water as 0 °C, very pure water remains a liquid until about -40 °C. Water crystallizes to ice in the presence of tiny nucleation particles in the atmosphere. These particles … Continue reading →... Read more »
Christner, B., Morris, C., Foreman, C., Cai, R., & Sands, D. (2008) Ubiquity of Biological Ice Nucleators in Snowfall. Science, 319(5867), 1214-1214. DOI: 10.1126/science.1149757
Pöschl U, Martin ST, Sinha B, Chen Q, Gunthe SS, Huffman JA, Borrmann S, Farmer DK, Garland RM, Helas G.... (2010) Rainforest aerosols as biogenic nuclei of clouds and precipitation in the Amazon. Science (New York, N.Y.), 329(5998), 1513-6. PMID: 20847268
- May 19, 2011
- 03:10 PM
- 956 views
Levees and the illusion of flood control
by Chris Rowan in Highly Allochthonous
Levees have their uses in protecting communities from flooding - but they also create the illusion of safety that promotes further settlement and development of floodplain lands. Continue reading →... Read more »
Olsen, J., Stedinger, J., Matalas, N., & Stakhiv, E. (1999) CLIMATE VARIABILITY AND FLOOD FREQUENCY ESTIMATION FOR THE UPPER MISSISSIPPI AND LOWER MISSOURI RIVERS. Journal of the American Water Resources Association, 35(6), 1509-1523. DOI: 10.1111/j.1752-1688.1999.tb04234.x
Pinter, N. (2005) ENVIRONMENT: One Step Forward, Two Steps Back on U.S. Floodplains. Science, 308(5719), 207-208. DOI: 10.1126/science.1108411
- May 4, 2011
- 11:50 PM
- 1,086 views
The many faces of earthquake triggering
by Chris Rowan in Highly Allochthonous
Can large earthquakes beget more large earthquakes? It’s an easy question to ask, but much more difficult to answer. Depending on the distance from, and time since, the initial earthquake, the processes that may result in ‘seismic triggering’ are very … Continue reading →... Read more »
McCloskey, J., Nalbant, S., & Steacy, S. (2005) Indonesian earthquake: Earthquake risk from co-seismic stress. Nature, 434(7031), 291-291. DOI: 10.1038/434291a
Velasco, A., Hernandez, S., Parsons, T., & Pankow, K. (2008) Global ubiquity of dynamic earthquake triggering. Nature Geoscience, 1(6), 375-379. DOI: 10.1038/ngeo204
Parsons, T., & Velasco, A. (2011) Absence of remotely triggered large earthquakes beyond the mainshock region. Nature Geoscience. DOI: 10.1038/ngeo1110
- February 24, 2011
- 12:52 AM
- 1,793 views
The scientist-journalist divide: what can we learn from each other?
by Chris Rowan in Highly Allochthonous
Last week, the journal Nature published two research papers on the effects of human-caused global warming on extreme precipitation events. I’m working on a post on the papers, and they’ve already received quite a bit of attention in the media. … Continue reading →... Read more »
Allan RP. (2011) Climate change: Human influence on rainfall. Nature, 470(7334), 344-5. PMID: 21331034
Schiermeier Q. (2011) Increased flood risk linked to global warming. Nature, 470(7334), 316. PMID: 21331014
- February 12, 2011
- 12:13 AM
- 1,281 views
Friday focal mechanisms: Chile’s persistent seismic gap
by Chris Rowan in Highly Allochthonous
The magnitude 8.8 earthquake that shook Chile in February 2010 occurred within a seismic gap - but new research suggests that it did not fill it. Continue reading →... Read more »
Lorito, S., Romano, F., Atzori, S., Tong, X., Avallone, A., McCloskey, J., Cocco, M., Boschi, E., & Piatanesi, A. (2011) Limited overlap between the seismic gap and coseismic slip of the great 2010 Chile earthquake. Nature Geoscience. DOI: 10.1038/ngeo1073
- February 8, 2011
- 08:32 AM
- 1,783 views
Pakistan floods: Predictable or predicted, but a disaster nonetheless
by Chris Rowan in Highly Allochthonous
Unusually heavy monsoon rains in July and August 2010 left large swaths of Pakistan underwater. At least 18 million people were affected by the flood, and it is estimated that, more than six months later, several hundred thousand remain without … Continue reading →... Read more »
Webster, P. J., Toma, V.E., & Kim, H.-M. (2011) Were the 2010 Pakistan floods predictable?. Geophysical Research Letters. info:/10.1029/2010GL046346
- January 25, 2011
- 07:26 AM
- 963 views
Geology is destiny: globally mapping permeability by rock type
by Chris Rowan in Highly Allochthonous
The first maps of the global distribution of the ease of subsurface water flow have been produced, and they are based on maps of rock type. Continue reading →... Read more »
Gleeson, T., Smith, L., Moosdorf, N., Hartmann, J., Dürr, H., Manning, A., van Beek, L., & Jellinek, A. (2011) Mapping permeability over the surface of the Earth. Geophysical Research Letters, 38(2). DOI: 10.1029/2010GL045565
- December 3, 2010
- 09:48 PM
- 1,022 views
Small rocky exoplanets galore
by Chris Rowan in Highly Allochthonous
A recent study presents some promising data regarding the abundance of rocky planets around other stars. Continue reading →... Read more »
Howard, A., Marcy, G., Johnson, J., Fischer, D., Wright, J., Isaacson, H., Valenti, J., Anderson, J., Lin, D., & Ida, S. (2010) The Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters. Science, 330(6004), 653-655. DOI: 10.1126/science.1194854
- September 14, 2010
- 07:48 AM
- 1,133 views
All quiet on the Alpine Fault?
by Chris Rowan in Highly Allochthonous
The Alpine fault has not ruptured since European settlement in the 1840s. Paleoseismology tells us that this is the longest it has gone in a millenium without generating a magnitude 8+ earthquake. Continue reading →... Read more »
Wells, A., & Goff, J. (2007) Coastal dunes in Westland, New Zealand, provide a record of paleoseismic activity on the Alpine fault. Geology, 35(8), 731. DOI: 10.1130/G23554A.1
- September 10, 2010
- 01:34 PM
- 1,161 views
Snow, water, digital imaging, metamorphism…and a guillotine!
by Chris Rowan in Highly Allochthonous
When water infiltrates past the ground surface and begins to percolate through the soil’s unsaturated zone, it doesn’t move downward like an even sheet. Instead, fast fingers of water move downward along pores, roots and other places where flow is … Continue reading →... Read more »
Williams, M., Erickson, T., & Petrzelka, J. (2010) Visualizing meltwater flow through snow at the centimetre-to-metre scale using a snow guillotine. Hydrological Processes, 24`(15), 2098-2110. DOI: 10.1002/hyp.7630
- September 1, 2010
- 09:07 AM
- 1,017 views
Diversity in the geosciences and the impact of social media
by Chris Rowan in Highly Allochthonous
In the September issue of GSA Today, you can find our article on The Internet as a resource and support network for diverse geoscientists. Where do we go from here? Continue reading →... Read more »
Jefferson, A.J., Hannula, K.A., Campbell, P.B., & Franks, S.E. (2010) The Internet as a resource and support network for diverse geoscientists. GSA Today, 20(9), 59-61. info:/10.1130/GSATG91GW.1
- August 26, 2010
- 12:43 PM
- 1,153 views
Yellowstone: what lies beneath
by Chris Rowan in Highly Allochthonous
The best evidence yet that the Yellowstone hotspot is the result of a mantle plume - one that had to burn through a subducting slab to get to the surface. Continue reading →... Read more »
Obrebski, M., Allen, R., Xue, M., & Hung, S. (2010) Slab-plume interaction beneath the Pacific Northwest. Geophysical Research Letters, 37(14). DOI: 10.1029/2010GL043489
- August 21, 2010
- 08:16 PM
- 1,303 views
Friday(ish) Focal Mechanisms: Samoa’s hidden rupture
by Chris Rowan in Highly Allochthonous
How what we thought was one great earthquake turned out to be two, or possibly even three, at the same time. Continue reading →... Read more »
Lay, T., Ammon, C., Kanamori, H., Rivera, L., Koper, K., & Hutko, A. (2010) The 2009 Samoa–Tonga great earthquake triggered doublet. Nature, 466(7309), 964-968. DOI: 10.1038/nature09214
Beavan, J., Wang, X., Holden, C., Wilson, K., Power, W., Prasetya, G., Bevis, M., & Kautoke, R. (2010) Near-simultaneous great earthquakes at Tongan megathrust and outer rise in September 2009. Nature, 466(7309), 959-963. DOI: 10.1038/nature09292
- August 18, 2010
- 12:01 PM
- 1,098 views
Snowball Earth no problem for sponges
by Chris Rowan in Highly Allochthonous
Evidence from numerous sources seems to be converging to suggest that sponges - the first animals - emerged much earlier than the beginning of the Cambrian, and apparently sailed through severe climatic events in the Cryogenian without much trouble at all. Continue reading →... Read more »
Maloof, A., Rose, C., Beach, R., Samuels, B., Calmet, C., Erwin, D., Poirier, G., Yao, N., & Simons, F. (2010) Possible animal-body fossils in pre-Marinoan limestones from South Australia. Nature Geoscience. DOI: 10.1038/ngeo934
- August 9, 2010
- 01:16 PM
- 1,322 views
Anne’s picks of the literature: river and floodplain sediments
by Chris Rowan in Highly Allochthonous
These four papers all attempt to understand what controls the sediments that make up the streambed and floodplain and that get preserved in the geologic record. White et al. look at how riffle positions are governed by valley width variations, while Jerolmack and Brzinski find striking similarities in grain size transitions observed in rivers and dune fields. Hart et al. examine the relationship between glacial advances and downstream sediment deposition, while Sambrook Smith et al. investigate ........ Read more »
White, J., Pasternack, G., & Moir, H. (2010) Valley width variation influences riffle–pool location and persistence on a rapidly incising gravel-bed river. Geomorphology, 121(3-4), 206-221. DOI: 10.1016/j.geomorph.2010.04.012
Jerolmack, D., & Brzinski, T. (2010) Equivalence of abrupt grain-size transitions in alluvial rivers and eolian sand seas: A hypothesis. Geology, 38(8), 719-722. DOI: 10.1130/G30922.1
Hart, S., Clague, J., & Smith, D. (2010) Dendrogeomorphic reconstruction of Little Ice Age paraglacial activity in the vicinity of the Homathko Icefield, British Columbia Coast Mountains, Canada. Geomorphology, 121(3-4), 197-205. DOI: 10.1016/j.geomorph.2010.04.011
Sambrook Smith, G., Best, J., Ashworth, P., Lane, S., Parker, N., Lunt, I., Thomas, R., & Simpson, C. (2010) Can we distinguish flood frequency and magnitude in the sedimentological record of rivers?. Geology, 38(7), 579-582. DOI: 10.1130/G30861.1
- July 14, 2010
- 11:34 AM
- 1,573 views
Anne’s picks of the June literature: Fluvial Geomorphology and Landscape Evolution
by Chris Rowan in Highly Allochthonous
How do rivers erode bedrock streams, during big floods, and in the presence of groundwater? Laboratory and accidental experiments are providing some cool new insights. Continue reading →... Read more »
Johnson, J., & Whipple, K. (2010) Evaluating the controls of shear stress, sediment supply, alluvial cover, and channel morphology on experimental bedrock incision rate. Journal of Geophysical Research, 115(F2). DOI: 10.1029/2009JF001335
Lamb, M., & Fonstad, M. (2010) Rapid formation of a modern bedrock canyon by a single flood event. Nature Geoscience, 3(7), 477-481. DOI: 10.1038/ngeo894
Pornprommin, A., & Izumi, N. (2010) Inception of stream incision by seepage erosion. Journal of Geophysical Research, 115(F2). DOI: 10.1029/2009JF001369
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