We use over 20 yrs (1996–2017) of the European Space Agency's (ESA) radar interferometry (InSAR) observations to investigate the postseismic deformation of the Tabas fold segment following the 1978 ...Mw 7.3 Tabas-e-Golshan earthquake in eastern Iran. We generated maps of satellite line-of-sight (LOS) velocity using two ERS descending tracks (1996–1999), one Envisat descending track (2003–2010), one Sentinel-1A descending track (2014–2017) and one Sentinel-1A ascending track (2014–2017). The LOS velocity shows afterslip continuing for at least 40 yrs after the earthquake. Elastic dislocation modelling based on the InSAR measurements reveals a decrease in postseismic velocities from 5.0 ± 0.8 mm/yr in 1996–1999 to 3.9 ± 0.6 mm/yr in 2003–2005, 3.0 ± 0.4 mm/yr in 2006–2010, and a present rate of 2.3 ± 0.6 mm/yr in 2014–2017. The rates decay with time, t, as 1/t, consistent with the predictions of a simple block-slider model. We then combine the InSAR rates and our previous estimates of the total earthquake slip derived from optical image matching and DEM differencing to explore the frictional behaviour of the Tabas fold. We obtained a rate-and-state parameter a−b≈0.003, indicating rate-strengthening frictional behaviour of the Tabas fault. We also inferred a minimum coseismic slip of 4.7 m, which might have driven bedding-plane shear at shallow depth, resulting in distributed fold growth and secondary faulting observed in the field. The results imply that both coseismic slip and afterslip have occurred in the same location. One possible mechanism to explain such a phenomenon is that the frictional parameter a−b is small enough to allow dynamic ruptures to propagate into rate-strengthening regions.
•We measured postseismic slip 40 years after the 1978 Tabas earthquake using InSAR.•Sentinel-1 measurements show a mean afterslip rate of 2.3 ± 0.6 mm/yr in 2014–2017.•The rates of afterslip decay with time, t, as 1/t.•We obtained a rate-and-state parameter a−b≈0.003, i.e. rate-strengthening behaviour.•Small frictional parameters allow seismic ruptures in rate-strengthening regions.
On December 12, 1963, people across Kenya joyfully celebrated independence from British colonial rule, anticipating a bright future of prosperity and social justice. As the nation approaches the ...fiftieth anniversary of its independence, however, the people's dream remains elusive. During its first five decades Kenya has experienced assassinations, riots, coup attempts, ethnic violence, and political corruption. The ranks of the disaffected, the unemployed, and the poor have multiplied. In this authoritative and insightful account of Kenya's history from 1963 to the present day, Daniel Branch sheds new light on the nation's struggles and the complicated causes behind them.
Branch describes how Kenya constructed itself as a state and how ethnicity has proved a powerful force in national politics from the start, as have disorder and violence. He explores such divisive political issues as the needs of the landless poor, international relations with Britain and with the Cold War superpowers, and the direction of economic development. Tracing an escalation of government corruption over time, the author brings his discussion to the present, paying particular attention to the rigged election of 2007, the subsequent compromise government, and Kenya's prospects as a still-evolving independent state.
ABSTRACT
Nearly all of the well-studied ancient globular clusters (GCs), in the Milky Way and in nearby galaxies, show star-to-star variations in specific elements (e.g. He, C, N, O, Na, and Al), ...known as ‘multiple populations’ (MPs). However, MPs are not restricted to ancient clusters, with massive clusters down to ∼2 Gyr showing signs of chemical variations. This suggests that young and old clusters share the same formation mechanism but most of the work to date on younger clusters has focused on N variations. Initial studies even suggested that younger clusters may not host spreads in other elements beyond N (e.g. Na), calling into question whether these abundance variations share the same origin as in the older GCs. In this work, we combine Hubble Space Telescope (HST) photometry with Very Large Telescope (VLT)/Multi-Unit Spectroscopic Explorer (MUSE) spectroscopy of a large sample of red giant branch (RGB) stars (338) in the Large Magellanic Cloud cluster NGC 1978, the youngest globular to date with reported MPs in the form of N spreads. By combining the spectra of individual RGB stars into N-normal and N-enhanced samples, based on the ‘chromosome map’ derived from HST, we search for mean abundance variations. Based on the NaD line, we find a Na difference of ΔNa/Fe = 0.07 ± 0.01 between the populations. While this difference is smaller than typically found in ancient GCs (which may suggest a correlation with age), this result further confirms that the MP phenomenon is the same, regardless of cluster age and host galaxy. As such, these young clusters offer some of the strictest tests for theories on the origin of MPs.
Militarizing Sri Lanka is a study of the militarization that has buttressed the war between the Sri Lankan state and the LTTE for over two decades. It highlights militarization as a process through ...which the ideology of militarism is shaped and shared in a manner that makes militant solutions to conflict a part of institutional structures and ways of thought. It foregrounds militarization as activity and agency, capable of adaptation and transforming society in significant ways; and as a deeply gendered, contingent and shifting process. It also analyzes both the construction and resistance to militarization and militarism, but in a manner that draws attention to their relationality rather than as self-evidently oppositional categories.
Please Let It Be Aliens Pierce, Catherine (American college teacher)
The Southern review (Baton Rouge),
06/2020, Letnik:
56, Številka:
3
Journal Article
La Corona en la España del siglo XXI se perfila como una institución constitucional eminentemente simbólica a la que apenas pueden adjudicársele unas atribuciones propiamente arbitrales o ...moderadoras. Su oportunidad y mantenimiento futuro en la sociedad sobre la que la magistratura unipersonal ejerce la jefatura del Estado depende de una racionalización absoluta que depure cualquier manifestación por parte de la Corona de actos o elecciones propias de trascendencia pública, así como de los resquicios que impidan el sometimiento pleno al Derecho de la institución y/o del comportamiento privado de sus circunstanciales ocupantes. La educación cívica en torno a la naturaleza meramente simbólica de la Corona aleja a toda la ciudadanía de futuras frustraciones colectivas derivadas de la sustitución de la forma de la jefatura del Estado actual por otra.
This book, which brings together leading academics and analysts, examines the extraordinary revival of the Scottish Conservative Party between 2011 and Ruth Davidson's shock resignation in 2019.
After months of speculation, it appears Ukraine’s counter-offensive is under way. As this next phase of fighting begins, our Russia and Eastern Europe editor, Arkady Ostrovsky, gives his three key ...takeaways on the latest developments in the war.
We use optical image correlation of historical aerial photographs, and modern satellite images to investigate the 1978 Mw 7.3 Tabas-e-Golshan thrust earthquake in eastern Iran. Correlation of images ...between 1974 and 1991 reveals a near-surface shortening component of ∼2.9 m across the margin of the Tabas fold, which is a combination of coseismic and postseismic deformation. Correlation of images between 1991 and 2013 shows a further ∼0.3 m of postseismic shortening. Using six pre-earthquake aerial photographs acquired in 1956 and stereo SPOT-6 imagery from 2013, we also generate pre- and post-earthquake digital elevation models (DEMs) for one of the main fold segments. Differencing of the two DEMs reveals a height change of ∼4.7 m. Elastic dislocation modelling of the 1974–2013 displacement field requires 7 m slip on a 50° dipping fault, extending from a depth of 0.1 km to 6 km at its base (the majority of slip, ∼6.5 m, occurred prior to 1991). Our results, combined with previous InSAR observations, indicate time-decaying shallow postseismic afterslip. It is likely that most of the afterslip occurred prior to 1991. The slip appears to dissipate in the near surface, and is accommodated as a narrow band of flexural slip on bedding planes. Comparison of the fault slip model with terrace heights measured from the SPOT-6 DEM suggests that the Tabas fold system may exhibit characteristic slip behaviour. Such behaviour would require a magnitude Mw 7.3 earthquake every ∼3500 years, based on the previously estimated shortening rate of ∼1.0 mm/yr. This study highlights the usefulness of historical imagery in investigating past earthquakes, thus providing new information about historical faulting in continental regions.
•Geodetic techniques for investigating earthquakes can be extended back to the 1970s.•We measured the co- and post-seismic displacements from the 1978 Tabas earthquake.•We show time-decaying shallow post-seismic afterslip following the 1978 earthquake.•The Tabas fold system may exhibit characteristic slip behaviour.•Such behaviour would require a magnitude Mw 7.3 earthquake every ∼3500 years.
The end-Permian mass extinction (EPME) led to a severe terrestrial ecosystem collapse. However, the ecological response of insects to the EPME remains poorly understood. Here, we report a new species ...assigned to
Chauliodites
,
Chauliodites tongchuanensis
sp. nov. (Grylloblattida: Chaulioditidae), from the Middle Triassic Tongchuan Formation of Shaanxi, northwestern China, and redescribe
Chauliodites fuyuanensis
(
Lin, 1978
) from the Lower Triassic Kayitou Formation of Yunnan and
Chauliodites nanshenghuensis
(
Lin, 1978
) comb. nov. from the Middle Triassic of Guizhou, southwestern China. Our results show that
Chauliodites
widely distributed after the EPME is probably related to the rise of isoetalean-dominated low-productivity terrestrial ecosystems.
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