DYNAMIC FLOW MODELING OF INFLATION AND DEFLATION CHARACTERISTICS FOR EFFUSIVE LAVA ERUPTIONS

Over the past decade several studies have highlighted the importance of developing analog models of lava flow physical characteristics. Recent field experience demonstrates that inflation and deflation characteristics in effusive flows can produce broad topographic profiles as result of crustal “breakouts” and dynamic flow passage “pileups”. The goal of this study is to utilize analog paraffin wax flow modeling to demonstrate the presence of inflation and deflation features in dynamic effusive flows as an interpretation of in-situ emplacement. For this study, Gulf Wax was utilized as an analog flow material. Utilizing a 500mL graduated cylinder and a candle making wax melter, the wax was heated to over 165°C. Pouring the heated wax into the 500mL graduated cylinder, 2mm, 4mm, 6mm, and 8mm steel balls were dropped into the graduated cylinder where a Vivitar 4k handheld camera on a tripod was used to record and calculate the velocity of the steel balls falling through the paraffin wax medium. Using Stoke’s Law principles, viscosity was calculated at 75°C, 100°C, 125°C, and 150°C. At this stage of the research, the reheated wax was poured onto an inclined slope surface with rough slope features to imitate typical volcanic slope and topographic profile. Subsequent modeling incorporated video recording using the handheld camera as well as thermal capture of dynamic crustal development with fixed position thermocouples and a handheld FLIR imager. Using the thermocouples and thermal imager, breakout development was recorded via thermal intensity measurements. This combined with recorded video evidence clearly demonstrated displacement of the analog medium whereby deflation of the main lobe, adjacent to the breakout lobe, represented clear topographical depressions. Similarly, thermal, and electro-optical recording of the analog medium encountering mechanical flow vectoring revealed flow inflation profiles at elevated points on the flow surface pathway. The recording and analysis of flow depression features near breakout zones demonstrates a mechanism for actual topographical depressions in flow fields. Additionally, the video and thermal documentation of inflation profiles in the presence of topographic obstructions to down-slope flows highlight key characteristics of ‘real-world” flow vectoring.