Strike-slip faulting, rotation, and along-strike elongation in the Kopeh Dagh mountains, NE Iran

The Kopeh Dagh is a linear mountain range separating the shortening in Iran from the stable, flat Turkmenistan platform. In its central part is an array of active right-lateral strike-slip faults that obliquely cut the range and produce offsets of several kilometres in the geomorphology and geological structure. They are responsible for major destructive earthquakes in the 19th and 20th centuries and represent an important seismic hazard for this now-populous region of NE Iran. These strike-slip faults all end in thrusts, revealed by the uplift and incision of Late Quaternary river terraces, and do not continue beyond the Atrak river valley, which forms the southern margin of the Kopeh Dagh. The cumulative offset on these strike-slip faults, and their associated rotation about vertical axes, can account for ∼60 km of N-S shortening. This value is similar to estimates of the Late Quaternary N-S right-lateral shear between central Iran and Afghanistan, which must be accommodated in NE Iran. The strike-slip faults also require ∼30 km of along-strike extension of the Kopeh Dagh, which is taken up by the westward component of motion between the South Caspian Basin and both Eurasia and Central Iran. It is probable that these motions occurred over the last ∼10 Ma

The Influence of Symbiosis on the Proteome of the <i>Exaiptasia</i> Endosymbiont <i>Breviolum minutum</i>

The cellular mechanisms responsible for the regulation of nutrient exchange, immune response, and symbiont population growth in the cnidarian–dinoflagellate symbiosis are poorly resolved. Here, we employed liquid chromatography–mass spectrometry to elucidate proteomic changes associated with symbiosis in Breviolum minutum, a native symbiont of the sea anemone Exaiptasia diaphana (‘Aiptasia’). We manipulated nutrients available to the algae in culture and to the holobiont in hospite (i.e., in symbiosis) and then monitored the impacts of our treatments on host–endosymbiont interactions. Both the symbiotic and nutritional states had significant impacts on the B. minutum proteome. B. minutum in hospite showed an increased abundance of proteins involved in phosphoinositol metabolism (e.g., glycerophosphoinositol permease 1 and phosphatidylinositol phosphatase) relative to the free-living alga, potentially reflecting inter-partner signalling that promotes the stability of the symbiosis. Proteins potentially involved in concentrating and fixing inorganic carbon (e.g., carbonic anhydrase, V-type ATPase) and in the assimilation of nitrogen (e.g., glutamine synthase) were more abundant in free-living B. minutum than in hospite, possibly due to host-facilitated access to inorganic carbon and nitrogen limitation by the host when in hospite. Photosystem proteins increased in abundance at high nutrient levels irrespective of the symbiotic state, as did proteins involved in antioxidant defences (e.g., superoxide dismutase, glutathione s-transferase). Proteins involved in iron metabolism were also affected by the nutritional state, with an increased iron demand and uptake under low nutrient treatments. These results detail the changes in symbiont physiology in response to the host microenvironment and nutrient availability and indicate potential symbiont-driven mechanisms that regulate the cnidarian–dinoflagellate symbiosis

1990年イラン北西部ルードバール地震(M7.3)の余震分布とそのテクトニクス的意味

One of the largest earthquakes in Iran occurred on June 20, 1990, at 21:00 UT at around Rudbar and Manjil Cities in Gilan Province, northwest Iran. An aftershock observation has been conducted around the source region from 30 days after the mainshock and has been continued for more than 5 months. The epicenters of the aftershocks are extending as long as 90km striking WNW-ESE in parallel with the trend of the northern and southern marginal longitudinal faults of the Qezel-Owzan basin along the Talesh-Alborz seismo-tectonic zone. A strike-slip fault, running along the aftershock zone on the uplifted side of the northern marginal fault, is proposed judging from the topographic map and the Landsat image. The part of the aftershock area southeast of the main shock epicenter is more active than the northwestern part. Particularly, microseismic activity is very high in the southeastern end close to Pakdeh, where remarkable surface fissures were observed. The Vp/Vs ratio is inferred as 1.88±0.60 for the region covered by the seismic network. The aftershock decay rate was such that p=1.5 for the modified Omori formula, although the p value for a short period of 4 days at the beginning of the observation was around 4.0.1990年6月20日21時00分13.12秒(世界時),イラン北西部ギーラーン州のルードバール市付近でM7.3の浅発地震が発生した.地震の30日後から余震観測を実施した. 60kmのスパンの3点観測網(Saravan, Abbar, Abtorsh)による観測は5ヶ月以上の期間続けられた.ほかに3ヶ所において2～5日間の短期観測(Masuleh, Bivarzin, Jirandeh)をおこなった