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The North Tehran Fault (NTF) is located at the southernmost piedmont of Central Alborz and crosses the northern suburbs of the Tehran metropolis and adjacent cities, where ∼15 million people live. Extending over a length of about 110 km, the NTF stands out as a major active fault and represents an important seismic hazard for the Iranian capital after historical seismicity. In order to characterize the activity of the NTF in terms of kinematics, magnitude and recurrence intervals of earthquakes, we carried out a first paleoseismological study of the fault within its central part between Tehran and Karaj cities. We opened a trench across a 3 m‐high fault scarp affecting Quaternary deposits. Our study shows that the scarp is the result of repeated events along a main N115°E trending shallow dipping thrust fault, associated with secondary ruptures. From the trench analysis and Infrared Stimulated Luminescence (IRSL) dating of fault‐related sediments, we interpreted between 6 and 7 surface‐rupturing events that occurred during the past 30 kyrs. Their magnitudes (estimated from the displacements along the faults) are comprised between 6.1 and 7.2. The two last events – the largest ‐ occurred during the past 7.9 ± 1.2 ka, which yields a Holocene slip rate of ∼0.3 mm/yr. The 7 earthquakes scenario suggests a regular periodicity with a mean recurrence interval of ∼3.8 kyrs. However, the two most recent events could correspond to the two largest historical earthquakes recorded in the area (in 312–280 B.C. and 1177 A.D.), and therefore suggest that the NTF activity is not regular. Key Points The first paleoseismological study along the North Tehran, Iran 6‐7 events occurred in the past 30 kyrs with magnitudes between 6.1 and 7.2 Mean return period is 3.8 kyrs, but irregular activity is likely

The 2019-11-1, Mw4.9 Le Teil earthquake occurred within the NE termination of the Cévennes faults system (CFS) in southern France, along the La Rouvière fault (LRF), an Oligocene normal fault which was not known to be potentially active. This shallow moderate magnitude reversefaulting event produced a 5 km-long surface rupture and strong ground shaking. No evidence of previous quaternary activity was observed in the morphology, raising the question whether the fault had been reactivated for the first time since the Oligocene or had broken the surface in the past without being detected in the morphology. To address this issue, we carried out paleoseismological investigations to analyze and characterize evidences of paleo-ruptures in Quaternary deposits. We discovered that at least one event prior 2019, occurred between 13.5 and 3.3 ka within the central part of the fault segment that broke in 2019, and that a possible earlier surfacerupturing event occurred within the northern part of this segment during the 16th century. Further investigations coupling sub-surface geophysical investigations and trenching are now carried out within the southern and northern segments of the LRF as well as along the other fault segments of the CFS.

The activity of the Damavand volcano (Central Alborz, northern Iran) began 1.8 Ma ago and continued up to 7 ka BP. Although the volcanic suite is clearly of shoshonitic affinity, only two petrographic types can be distinguished in the studied lavas: (1) weakly differentiated absarokites (49 < %SiO 2  < 51), scattered around the volcano but with a regional extension, (2) highly differentiated banakites (59 < %SiO 2  < 63), which form the bulk of the 4,000 m thick volcanic pile. All lavas are alkalic (3.7 < %K 2 O < 5), REE and LILE-rich (e.g., 85 < La < 148 ppm; 9 < Th < 32 ppm) and show highly fractionated REE patterns (69 < La/Yb < 115) and pronounced Nb–Ta negative anomalies. The absarokites are characterised by Sr (0.7045–0.7046) and Nd (0.51266–0.51269) isotope compositions close to the Bulk Earth values, and distinct from those of the banakites (0.7047 <  87 Sr/ 86 Sr < 0.7049, 0.51258 <  143 Nd/ 144 Nd < 0.51262). The Pb isotope ratios are also slightly lower in the absarokites than in the banakites (18.71 <  206 Pb/ 204 Pb < 18.77, 15.62 <  207 Pb/ 204 Pb < 15.63, 38.85 <  208 Pb/ 204 Pb < 38.91, and 18.77 <  206 Pb/ 204 Pb < 18.84, 15.62 <  207 Pb/ 204 Pb < 15.64, 38.94 <  208 Pb/ 204 Pb < 39.06, respectively). Overall, there is a clear tendency towards higher Sr, Pb and lower Nd isotope ratios with increasing degree of differentiation. This study suggests that the absarokites result from a low degree of partial melting (∼5%) of a highly metasomatized mantle source, which inherited its characteristics from an old subduction setting. The initiation of volcanic activity 1.8 Ma ago results from variations in the lithospheric thermal regime, probably related to lithospheric delamination as proposed for Anatolia (Pearce et al. 1990 ). The banakites are mainly generated by extensive fractional crystallisation (∼70%) of the absarokitic magma, with a limited amount (a few percents) of assimilation of an old crustal component, in the form of bulk assimilation or AFC processes, which both can explain the Sr, Nd and Pb isotope data.

In spite of an increasing number of paleoseismic studies carried out over the last decade along the Himalayan Arc, the chronology of historical and prehistorical earthquakes is still poorly constrained. In this paper, we present geomorphologic and paleoseismic studies conducted over a large river-cut exposure along the Main Fontal Thrust in southwestern Bhutan. The Piping site reveals a 30 m high fault-propagation fold deforming late Holocene alluvial deposits. There, we carried out detailed paleoseismic investigations and built a chronological framework on the basis of 22 detrital charcoal samples submitted to radiocarbon dating. Our analysis reveals the occurrence of at least five large and great earthquakes between 485±125 BCE and 1714 CE with an average recurrence interval of 550±211 years. Coseismic slip values for most events reach at least 12 m and suggest associated magnitudes are in the range of Mw 8.5–9. The cumulative deformation yields an average slip rate of 24.9±10.4 mm yr−1 along the Main Frontal Thrust over the last 2600 years, in agreement with geodetic and geomorphological results obtained nearby.

We present 35 new burial ages (27 sites) based on 26Al / 10Be ratios of terrestrial cosmogenic radionuclides measured in clasts and sediments deep within 12 caves in the southern Massif Central, France. Our results, together with previously published burial ages, verify that cave morphogenesis has been continuously active in this region for at least the past ∼ 6 Myr. Combining sample burial ages with their associated cave elevation above the modern stream bed gives a mean regional incision rate of 88 ± 5 m Ma−1 for the Grands Causses area. South of the Cevennes Fault Zone bordering the Grands Causses, the incision rate is 43 ± 5 m Ma−1, suggesting that this difference might be accommodated by the fault zone. Sediment burial ages from caves which are not located on river valley flanks or cliff walls are surprisingly too young compared to their expected ages when calculated using this regional average river incision rate. This suggests that the classical epigenic speleogenesis model that presumes a direct correlation between cave level development and regional base level lowering does not apply for the study area. Therefore, we propose that regional speleogenesis is mainly controlled by the removal of ghost rocks by headward erosion from river canyons to central parts of the plateaus, emptying incipient primokarst passages to create cave systems. Our results suggest a continuum process from hypogene primokarst composed of passages filled with ghost rock to one of epigene karst dynamics emptying these passages and creating cave networks. We propose that these processes are the major mechanism in the southern Massif Central that initiates speleogenesis and controls the geometry of the networks. In this region, tiered karst cannot be associated with the pace of incision of the major rivers but must be explained by former ghost rock (or hypogene) processes.

The evolution of intraplate orogens is still poorly understood. Yet, it is of major importance for understanding the Earth and plate dynamics, as well as the link between surface and deep geodynamic processes. The French Massif Central is an intraplate orogen with a mean elevation of 1000 m, with the highest peak elevations ranging from 1500 to 1885 m. However, active deformation of the region is still debated due to scarce evidence either from geomorphological or geodetic and seismologic data. We focus our study on the southern part of the Massif Central, known as the Cévennes and Grands Causses, which is a key area to study the relationship between the recent geological deformation and landscape evolution. This can be done through the study of numerous karst systems with trapped sediments combined with the analysis of a high-resolution digital elevation model (DEM). Using the ability of karst to durably record morphological evolution, we first quantify the incision rates. We then investigate tilting of geomorphological benchmarks by means of a high-resolution DEM. We finally use the newly quantified incision rates to constrain numerical models and compare the results with the geomorphometric study. We show that absolute burial age (10Be∕26Al on quartz cobbles) and the paleomagnetic analysis of karstic clay deposits for multiple cave system over a large elevation range correlate consistently. This correlation indicates a regional incision rate of 83 +17/-5 m Ma−1 during the last ca. 4 Myr (Pliocene–Quaternary). Moreover, we point out through the analysis of 55 morphological benchmarks that the studied region has undergone a regional southward tilting. This tilting is expected as being due to a differential vertical motion between the northern and southern part of the studied area. Numerical models show that erosion-induced isostatic rebound can explain up to two-thirds of the regional uplift deduced from the geochronological results and are consistent with the southward tilting derived from morphological analysis. We presume that the remaining unexplained uplift is related to dynamic topography or thermal isostasy due to the Massif Central Pliocene–Quaternary magmatism. Integrating both geochronology and morphometrical results into lithospheric-scale numerical models allows a better understanding of this intraplate–orogen evolution and dynamic. We assume that the main conclusions are true to the general case of intraplate deformation. That is to say, once the topography has been generated by a triggering process, rock uplift is then enhanced by erosion and isostatic adjustment leading to a significant accumulation of mainly vertical deformation.

The North Tehran Fault is located at the southernmost piedmont of Central Alborz, north of Iran. It stands out as a major active fault menacing directly the city of Tehran, a 12 million people metropolis, and would have been the source of several major historical earthquakes in the past. The fault zone extends up to 110km and corresponds mainly to a reverse fault mostly crossing the northern suburbs of the Tehran metropolis, although NTF in its eastern part is characterized more as a left lateral strike slip active fault. We carried out a paleoseismological study of the fault zone in order to determine whether the fault was activated during the Holocene, and to define the characteristics of its activity in terms of kinematics and magnitude. Here in this paper we present only a part of our paleoseismological investigations trench TE2. Observations fromtwo trenches dug across the North Tehran fault scarp reveal evidence for a maximum of six surface-rupturing events within the late quaternary. According to the empirical relationships among average displacement per event and Moment magnitude [25], we can estimate six events Mw~ 6.5 associated with these ruptures in TE2 trench.

Although clinicians frequently add a second medication to an ineffective antidepressant, randomized trials comparing augmentation medications are lacking. In this study, adult outpatients with nonpsychotic major depressive disorder who had not had a remission during citalopram therapy were assigned to sustained-release bupropion or buspirone and had similar remission rates on the basis of clinician and self-reports. Several important secondary measures favored citalopram plus bupropion over citalopram plus buspirone. Adult outpatients with nonpsychotic major depressive disorder who had not had a remission during citalopram therapy were assigned to bupropion or buspirone and had similar remission rates. Several important secondary measures favored citalopram plus bupropion over citalopram plus buspirone. Numerous studies, 1 – 7 including one by Rush et al. 8 reported elsewhere in this issue of the Journal, have shown that major depressive disorder often requires more than one step of treatment to elicit a remission of symptoms. Frequently, a second medication is added to augment the first. 4 , 6 Augmentations of an initial selective serotonin-reuptake inhibitor (SSRI) with sustained-release bupropion, buspirone, mirtazapine, or dopamine agonists (e.g., pramipexole, dextroamphetamine, and methylphenidate) have been evaluated largely in open case series conducted in symptomatic volunteers with few psychiatric or general medical coexisting illnesses. 9 No randomized, controlled, prospective trials have directly compared two or more . . .

Adult outpatients with a nonpsychotic major depressive disorder received sustained-release bupropion, sertraline, or extended-release venlafaxine after a lack of response to or an inability to tolerate the selective serotonin-reuptake inhibitor (SSRI) citalopram. Approximately one in four patients had a remission of symptoms after switching to another antidepressant. All these medications provided a reasonable second-step choice for depressed outpatients who did not have a remission with or could not tolerate the SSRI. Adult outpatients with a nonpsychotic major depressive disorder received bupropion, sertraline, or venlafaxine after a lack of response to or an inability to tolerate citalopram. Approximately one in four patients had a remission of symptoms after switching to another antidepressant. Major depressive disorder is associated with substantial morbidity, mortality, family burden, and health care costs. 1 Since no single treatment is uniformly effective, 2 – 4 subsequent interventions are often needed. Second-step treatments include augmenting the first agent with a second or discontinuing the first agent and beginning a second (switching). The Sequenced Treatment Alternatives to Relieve Depression (STAR*D) Trial used an equipoise, stratified, randomized design to evaluate the relative efficacy and tolerability of various antidepressant treatments for outpatients with nonpsychotic major depressive disorder who had a lack of remission or could not tolerate the selective serotonin-reuptake inhibitor (SSRI) citalopram (Celexa, Forest Pharmaceuticals) . . .

Objectives: Increased energy expenditure (EE) has been proposed as an important mechanism for weight loss following Roux-en-Y gastric bypass (RYGB). However, this has never been investigated in a controlled setting independent of changes in energy balance. Similarly, only few studies have investigated the effect of RYGB on glycaemic control per se . Here, we investigated the effect of RYGB on EE, appetite, glycaemic control and specific signalling molecules compared with a control group in comparable negative energy balance. Subjects/Methods: Obese normal glucose-tolerant participants were randomized to receive RYGB after 8 ( n =14) or 12 weeks ( n =14). The protocol included a visit at week 0 and three visits (weeks 7, 11 and 78) where 24-h EE, appetite and blood parameters were assessed. Participants followed a low-calorie diet from weeks 0–11, with those operated at week 12 serving as a control group for those operated at week 8. Results: Compared with controls, RYGB-operated participants had lower body composition-adjusted 24-h EE and basal EE 3 weeks postoperatively (both P <0.05) but EE parameters at week 78 were not different from preoperative values (week 7). Surgery changed the postprandial response of glucagon-like peptide-1 (GLP-1), peptide YY 3–36 (PYY), ghrelin, cholecystokinin, fibroblast growth factor-19 and bile acids (all P <0.05). Particularly, increases in GLP-1, PYY and decreases in ghrelin were associated with decreased appetite. None of HOMA-IR (homeostasis model assessment-estimated insulin resistance), Matsuda index, the insulinogenic index, the disposition index and fasting hepatic insulin clearance were different between the groups, but RYGB operated had lower fasting glucose ( P <0.05) and the postprandial glucose profile was shifted to the left ( P <0.01). Conclusions: Our data do not support that EE is increased after RYGB. More likely, RYGB promotes weight loss by reducing appetite, partly mediated by changes in gastrointestinal hormone secretion. Furthermore, we found that the early changes in glycaemic control after RYGB is to a large extent mediated by caloric restriction.