Soil resilience assessment using soil profile descriptions and Analytic Hierarchy Process in Mediterranean mountains considering diverse fire occurrences

Wildfires are complex natural phenomena that exert significant impacts on landscapes,societies,and economies.Understanding the concept of resilience is crucial in mitigating its possible negative impacts,as it involves preparing for,responding to,and recovering from wildfires.This research aims to demonstrate the utility of in situ soil profile description in assessing land use resilience using an Analytic Hierarchy Process(AHP)through an expert panel survey.The study examines a catchment located in the Balearic Islands,considering two fire occurrences(once and twice),comparing abandoned agricultural terraces and natural hillslopes.The results demonstrated that the priority ranking of variables to assess soil profile resilience against wildfires,determined by a panel of 10 experts,identified horizon depth(25.1%),slope inclination(21.5%),and hydrological connectivity(16.6%)as the most crucial factors.Other variables,such as number and size of roots,structure of pedal soil material,size class structure,and rock fragments,also contributed to resilience but to a lesser extent,with scores ranging from 5.7%to 9.6%.Analyzing the priorities established by the experts using AHP,the results showed that the least resilient soil horizon was H1 of the control hillslope,especially under high and low connectivity processes,which aligned with the loss of superficial soil horizons after one and two wildfires.Hillslopes showed greater changes in resilience after occurring wildfires compared to terraces,with the most significant alterations occurring after the second wildfire event.This study addresses a significant knowledge gap in the field by highlighting the interconnectedness of wildfires,resilience,and land use,providing insights into land management strategies for wildfire-prone regions.

Joint land-sea seismic survey and research on the deep structures of the Bohai Sea areas

This paper presents the survey and research work of two land-sea profiles in the Bohai Sea, China, carried out in 2010-2011, including the seismic sources on land and in the sea, the ocean bottom seismographs （OBS） and their recovery, the coupling of OBS and the environment noise in sea area, the data quality of OBSs, and the result of data analysis. We focused on the investigation of crustal structures revealed by the two NE／EW-trending joint land-sea profiles. In combination with the Pn-velocity distribution and gravity- magnetic inversion results in the North China Craton, we propose that the undulation of the Moho interface in the Bohai and surrounding areas is not strong, and the lithospheric thinning is mainly caused by the thinning of its mantle part. The research result indicates that obvious lateral variations of Moho depth and seismic velocity appear nearby all the large-scale faults in Bohai Sea, and there is evidence of underplating and reforming of the lower crust by mantle material in the Bohai area. However, geophysical evidence does not appear to support the ＂mantle plume＂ or ＂delamination＂ model for the North China Craton destruction. The crustal structure of the Bohai Sea revealed ＂a relatively normal crust and obviously thinned mantle lid＂, local velocity anomalies and instability phenomena in the crust. These features may represent a combined effect of North China-Yangtze collision at an early stage and the remote action of Pacific plate subduction at a late stage.

Pre-rig mobilization hazard evaluation in offshore oil and gas prospect drilling:A case study of TM field,offshore Niger Delta

TM Field,located offshore Niger Delta in the Gulf of Guinea(Nigeria),has been evaluated for potential drilling hazards prior to the drilling of a proposed oil well.This is in a region where potential hazards that could inhibit successful drilling exercise have not been adequately studied.The study adopted the modern technique of offshore geohazard evaluation that relies mainly on suites of geophysical and shallow geological investigations which include ocean bathymetry using multi-beam echo sounder,sidescan sonar,sub-bottom profiler,magnetic,and 2D-high resolution seismic reflection surveys.The results were integrated to draw inferences about the risk potential of the field.From the bathymetric survey,water depths were found to range from 345 m to 650 m LAT,with seabed relief being 305 m.Water depth at the proposed well location was found to be approximately 450 m and the seabed was found to slope in the northwestern direction.Seafloor gradient was computed as 0.05 across the whole area.Two shallow sub-surface stratigraphic units,labelled A and B,were delineated.Unit A was directly beneath the seafloor and seemed to be composed mainly of clayey/silty sand.Its thickness ranged from 6 m to 70 m across the study area.Unit B appeared to be a layer of sand and its total thickness was not fully delineated.Observable kinks and displacements at the flanks of seabed undulations/depressions on subbottom profiler sections suggested that the depressions may be fault-controlled.On the map generated from the marine magnetic data,a magnetic fault was delineated and this appeared to be coincident with the shallower of the two buried faults on the cross-line seismic section cutting through the proposed well-head location.Interpreted seismic reflection data presented this fault as being inactive.Most of the faults mapped,especially the buried ones,appeared to be inactive except a few.Regions with mapped amplitude anomalies are to be avoided during rig-mobilization operations.Though engineering conditions are expected to vary vertically since layers occur as intercalation,significant lateral variation is not expected within uniform layers of bed.Risk of punch-through associated with clayey formation is expected to be low because the geologic layers are not uniformly and entirely clay.The proposed wellhead location was found to be free of potential hazard sources.

Quantifying cold front induced water transport of a bay with in situ observations using manned and unmanned boats

The generation of high-resolution data is increasingly important in understanding the complexities of coastal ocean and developing sound management strategies, especially in view of the long-term impact of severe weather systems. The impact of severe weather systems, when integrated over time, can be significant when compared with tidal oscillations. This paper presents a study of water transport out of Vermilion Bay in response to a short, intense event associated with a passing atmospheric cold front, and reports the application of an Acoustic Doppler Current Profiler （ADCP） mounted on an Automated Surface Craft （ASC）, known as the auto-boat or unmanned boat, developed in our lab at the Louisiana State University, to generate high resolution data accurately at a fraction of the cost of a manned boat. In our study, we used a manned boat and an unmanned boat, each for over 24 h to cover an entire diurnal tidal cycle, to measure flow velocity profiles to calculate the total transport. A stationary ADCP was deployed in the Southwest Pass of the Vermilion Bay from May 2009 to April 2012, providing data almost continuously （with only one major gap）, with a 717-day record of water transport between the northern Gulf of Mexico and Vermilion Bay, and demonstrates the importance of the pass in water transport.