Barishal has recently gone through intense land use and land cover changes (LULC). This study aims to assess the changes of land use of Barishal, which were surveyed from 2000 to 2020 by utilizing Landsat TM, ETM + & OLI-TIRS imageries. The ArcGIS-10.4 & the ERDAS-14 Imagine software were used to deal with satellite images and surveyed measurable data for land cover change evaluation of the study area. Both pre- and post-classification change detection scenarios and NDVI analysis were observed to assess the change result from 2000 to 2020. Maximum likelihood classification was utilized to create unsupervised land cover category (water body, urban, fallow, agriculture, vegetation and lowland). After ensuring acceptable value for each classified image (82.16% for 2020, 76.15% for 2010 & 70.96% for 2000 with Kappa values of 0.64, 0.62 & 0.62 for 2020, 2010 and 2000), a change detection study was performed. This study discovered that the highest growth 69.22% of urban area has been improved within 20 years followed by 49.75% and 21.74% of water bodies, fallow lands; whereas the annual change rate was 14.95%, 7.91% and 10.31% respectively. In contrast, 16.28%, 10.48% and 37.20% of vegetation, agriculture and lowland had been reduced and an (-) annual change rate of 16.03%, 7.15% and 9.99% respectively. In addition, NDVI analysis was also observed a decreasing trend of the vegetation and agricultural lands. The results of this assessment could be supportive to design and appliance significant managing appraisals to protect the agricultural degradation, fruitless urbanization of Barishal district.

A unique, consistent, and uniform earthquake catalog is crucial for assessing seismic hazards in any locality. This study aims at compiling and processing a better uniform earthquake catalog, using this catalog to identify the probable subduction zone, and assessing seismicity parameters for Bangladesh. The study area is bounded by the geographical limits 16–29°N and 86–96°E. It includes a sum of 48,342 events which are compiled as 1.0 to 8.5 magnitudes (MW) and time period from 1548 to 2020 yrs. Uniformization is made between the body, surface wave, and moment magnitude scales to unify the catalog in terms of MW. For seismic hazard assessment or prediction studies, this catalog comprises earthquake events from Bangladesh and adjoining regions. The assessed MC obtained is around 4.0–5.0, which leads to a, b value varying between 0.71–1.12 and an a value varying between 4.85–7.12. The findings show that the MC is lower at the border of the Chittagong-Sylhet through Hill tracts than the northern part of the area with an MC 4.5–5.0 and a, b value close to 1.00. The results indicate that the study area is a seismically highly active zone in the context of seismicity parameters. Finally, the compiled catalog, seismicity of the area and a probable deformation front are presented and are recommended for use in assessing seismic hazard analysis in Bangladesh.