Geomorphology, the study of landforms and their formative processes, is a multidisciplinary field most strongly associated with the geographical and geological sciences. It encompasses numerous subfields of specialization that are not necessarily mutually exclusive. Like all disciplines, what geomorphology is like today derives in part from the practitioners, ideas, controversies, and events involved in its development. This paper presents a brief perspective and overview of the history of geomorphology as an introduction to the subsequent chapters in the volume, each of which focuses on a specific period of the discipline's history or on concepts that have figured prominently in its past development or current status. A brief summary of the following 18 papers in this volume provides insight into the range of ideas and methods that are engaged in the theory and practice of geomorphology. The volume as a whole provides historical and thematic context for the subsequent volumes in the Treatise on Geomorphology.

The main volcanological concept is shown and expressed so that any volcano can be understood easily. Volcanic products are listed and explained in plain language from lava flow to various pyroclastic products. The volcanic products have been explained schematically and their textural, field relationships characteristics are highlighted. The origin of magma within the interior of the Earth is also explained and the link between mantle and crust has been shown. The relationship among crust, mantle, and core has been highlighted embracing the source-to-surface model. An updated explanation of the Pyroclastic Density Currents (PDC) has been done to perceive their danger. Some of the most successful Volcanology books have been used. This will help the students, with a passion for Volcanology, to understand the principles of Volcanology. <...>

After a well is drilled, a string of geophysical instruments (called a sonde) is placed into the borehole to record the geophysical properties of the subsurface strata. The data are digitally recorded in a nearby logging facility (commonly a logging vehicle for land-based rigs) and transferred to a paper log and/or saved as a digital .las data file. It is very common to get both a digital and paper copy of the well.