Yellowstone is a large restless caldera that contains many dynamic thermal areas that are the surface expression of the deeper magmatic system. In 2018, using a Landsat 8 nighttime thermal infrared image, we discovered the emergence of a new thermal area located near Tern Lake on the northeast margin of the Sour Creek dome. A high-spatial-resolution airborne visible image from August 2017 revealed a large (~33,300 m²) area of recently fallen trees, mostly devoid of vegetation, with bright soil, similar to other nearby thermal areas. Field observations in August 2019 confirmed that this was a steam-heated, acid-sulfate thermal area, with an arc-shaped zone of hydrothermally altered soil and heated ground, with surface temperatures of 60–80°C, several steaming fumaroles, and boiling temperatures (93°C) just beneath the surface. Fallen trees in contact with warm ground were being carbonized, yet new trees were growing in some cooler areas. Observations of stressed or dying vegetation from archived satellite and airborne remote sensing data going back to 1994 indicated that this thermal area started emerging around 2000. It increased in size slowly until around 2005, when the radiative heat output started measurably increasing. From 2005 to 2012, it grew more rapidly; and from 2012 through 2019, the growth rate slowed and the heat output stabilized. We predict that this stabilizing trend will continue in the coming years. The initial formation of this new thermal area was not clearly linked to any distinct seismic or geodetic events, although the period of rapid growth partly coincided with a period of rapid local uplift, possibly suggesting a causative relationship. The identification of this emerging thermal area illustrates the importance of satellite thermal infrared imaging combined with high-spatial-resolution remote sensing data and field observations for mapping, measuring, and monitoring Yellowstone's thermal areas. It is also an example of the dynamics we expect to observe within large caldera systems like Yellowstone, where changes in the size and distribution of thermal areas are normal and do not indicate an impending eruption nor any significant changes in the broader magmatic system.

黄石是一个巨大的不安火山口，其中包含许多动态热区，是深层岩浆系统的表面表现。在2018年，利用Landsat 8夜间热红外图像，我们发现了位于Sour Creek圆顶东北边缘特恩湖附近的一个新热区。2017年8月的高空间分辨率机载可见图像显示了大（〜33,300 m ²）与其他附近的热区相似，最近倒下的树木几乎没有植被，土壤明亮的区域。2019年8月的实地观察证实，这是一个蒸汽加热的酸硫酸盐热区，具有一个弧形的热液蚀变的土壤和加热的地面区域，地表温度为60-80°C，有多个蒸喷气孔和沸腾的表面下的最高温度（93°C）。与温暖的地面接触的倒下的树木正在被碳化，但是在一些凉爽的地区却正在生长新的树木。从1994年存档的卫星和机载遥感数据中观察到的紧张或濒临灭绝的植被的观察结果表明，这个热区在2000年左右开始出现。它的大小缓慢增加，直到2005年左右，辐射热输出开始明显增加。从2005年到2012年，它增长更快；从2012年到2019年，增长率放慢，热量输出趋于稳定。我们预计，这种稳定趋势将在未来几年继续。尽管快速增长的时期与局部快速上升的时期部分重合，但这新的热区的初始形成与任何明显的地震或大地事件都没有明确的联系，这可能表明存在因果关系。对这一新兴热区的识别说明了卫星热红外成像与高空间分辨率遥感数据和野外观测相结合对绘制，测量和监控黄石热区的重要性。这也是我们希望在大型火山口系统（如黄石公园）中观察到的动力学的一个例子，