Letter from editor
Authors: Vargas J. Carlos A. 
Published: March 2015

<div class="page" title="Page 1"><div class="section"><div class="layoutArea"><div class="column"><p>Welcome to Earth Sciences Research Journal, Volume 18, Number 1. More than 20 years have passed since we decided to be part of the scientific world in geology, seismology, geophysics, geodesy, meteorology, oceanography, planetary sciences, and so many other fields. We raised our voice to say to the world that in Colombia, there is a Journal committed to providing the highest level of manuscript in Earth Sciences.</p><p><span>It has been not an easy road, but we are here. This 2014 has been full of challenges moving us to find the best ways to present new manuscripts. Our Volume 18 was made possible by the non-profit cooperation of authors and reviewers working hand-in- </span><span>hand with us. </span></p><p><span>In this volume, we are presenting to the eyes of scientific world nine papers coming from three different continents, with contributions by people from seven countries. Our first paper comes from Egypt, about an aeromagnetic data analysis in the region of Fayoum-Cairo. This work regarding the October 12, 1992 earthquake, suggests how the new tectonics of Africa’s northeast is predominant in this area. From Turkey, our second manuscript obtained a new, important, more up-to-date and more reliable relationship between surface wave magnitude and rupture length for earthquakes in that country. The results obtained in this study will give some useful and up-to-date information to authors whose studies are focused in this area. </span></p><p><span>In the field of hydrogeology, the third article analyzes the hydrogeochemistry of shallow groundwater in the Yellow River alluvial plain. The results suggest that the shallow groundwater in the study area is fresh to moderately mineralized water. The assessment of samples shows how this water is acceptable for agricultural use but is not potable. From China, too, an interesting paper about the petrography and mineralogy of biotites within the Wushan granodiorite is presented. The formation conditions of these biotites are also determined and the significance of these minerals in terms of petrogenesis and mineralization is </span><span>discussed. </span></p><p><span>From India, where climate change is a topic trend, a study attempts to provide information on climate variability and its impacts on runoff in the Kosasthaliyar sub-basin. From Nigeria, a work related to aromatic biological markers are used for assessing thermal maturity of source rocks in the Campano-Maastrichtian Mamu formation. Results of this study show how these maturity values indicate that the coal and shale extracts are marginally mature for hydrocarbon generation. </span></p></div></div></div></div><div class="page" title="Page 2"><div class="layoutArea"><div class="column"><p><span>We invite you to read also three South American papers. From Colombia, the manuscripts titled “Enhancing time resolution by stabilized inverse filter and Q estimated on instantaneous spectra” and “Hydrocarbon Production Scenarios in Colombia. Review of Field Sizes, Hydrocarbon Reserves and Expectations of Conventional and Unconventional Resources” are presented. From Chile comes the paper “Uncertainty in rainfall input data in a conceptual water balance model: effects on outputs and implications for predictability”. </span></p><p><span>Thanks to every one of you and enjoy this issue of the ESRJ. </span></p></div></div></div>