![]() ![]() The LERZ map was also heavily influenced by earlier Pu‘u ‘Ō‘ō maps. ![]() A road shown on top of a lava flow would suggest that it survived or was recently rebuilt. In the stacking order, a lava flow is always on top, because it effectively destroys everything that was once in its place. For example, roads are shown in shades of gray because other colors could cause confusion, with blue often used for streams or paths of steepest descent, and red reserved for lava flows. In designing this map, GIS analysts considered various logical rules for symbolizing and stacking the layers. The first eruptive fissure opened in the Leilani Estates subdivision in the late afternoon of May 3, and HVO released its first eruption map the next morning. When magma intruded into the LERZ in early May 2018, HVO prepared a template map of the region that could be ready for rapid distribution if/when lava erupted to the surface. Using commercial GIS software, the user creates a stack of "layers," such as labels, roads, and political boundaries that together form a map. Geological Survey staff on their toes for over three months.Ĭomputer programs known as Geographic Information Systems (GIS) have been the preferred tool of USGS cartographers for many years. Still, this summer's dynamic situation in lower Puna presented its own unique set of cartographic (map-making) challenges, which kept HVO and other U.S. This was not the first time such maps have been in the public eye, as regular maps of Pu‘u ‘Ō‘ō lava flows have been posted to HVO's website for many years. Shaded purple areas depict lava flows erupted in 1840, 1955, 1960, and 2014-2015. Minor activity within the fissure 8 cone continued into early September 2018 but did not expand the flow margins. There has been no lava flow expansion since August 9, 2018. This map of Kīlauea Volcano's lower East Rift Zone, created by USGS Geographic Information Systems (GIS) analysts, shows the extent of the 2018 lava flows (pink), which covered an area of about 35.5 sq km (13.7 sq mi) and added about 875 acres of new land to East Hawai‘i. ![]()
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