Digital elevation model of the lava dome in the crater of Mount St. Helens, October 23, 1980

The catastrophic, explosive eruption of Mount St. Helens, Washington, on May 18, 1980, is the most well-known eruption of the volcano. Less well known is that the May 18 eruption marked the beginning of a period of eruptive activity that lasted through 1986. Beginning in October 1980, a series of 17 dome-building episodes added millions of cubic meters of lava to the crater floor. Most of the growth occurred when magma extruded onto the surface of the dome, forming lava flows approximately 198 to 396 meters (650 to 1,300 feet) long and 20 to 40 meters (65 to 130 feet) thick. This data release includes a 2-meter resolution digital elevation model (DEM) and a corresponding hillshade raster. These were derived from a previously unpublished 1:4,000 scale topographic contour map, which was based on aerial photographs taken on October 23, 1980. The map was created by the USGS for use during the response to the eruption.

1980年5月18日华盛顿州圣海伦斯火山（Mount St. Helens）的灾难性爆发式喷发，是该火山最广为人知的一次喷发事件。鲜为人知的是，此次5月18日的喷发开启了一段持续至1986年的火山活动周期。自1980年10月起，共计17次穹顶增生事件向火山口底部堆积了数百万立方米的熔岩。绝大多数熔岩增生发生在岩浆被挤压至穹顶表面的过程中，形成了长度约198至396米（650至1300英尺）、厚度20至40米（65至130英尺）的熔岩流。本次公开数据集包含一套2米分辨率的数字高程模型（DEM）及其配套的晕渲地貌栅格（hillshade raster）。上述数据源自一份此前未公开的1:4000比例尺地形等高线图，该图基于1980年10月23日拍摄的航空影像制作，由美国地质调查局（USGS）为本次火山喷发的应急响应工作编制。