Take a tour through volcanic history on the edge of the Sierra Nevada near Mammoth Lakes, California. Between the tall granite peaks to the west and the Basin and Range province to the east, overlapping volcanic complexes imprint the landscape with a collection of craters, cones, and calderas. The area, still restless today, draws interest from geologists studying Earth’s processes and from planetary scientists exploring its commonalities with volcanic terrain elsewhere in our solar system.
游览加利福尼亚州猛犸湖附近内华达山脉边缘的火山历史。在西边高大的花岗岩山峰和东边盆地山脉省之间，重叠的火山群在景观上留下了一系列火山口、火山锥和破火山口的印记。该地区至今仍然动荡不安，吸引了研究地球过程的地质学家和探索其与太阳系其他火山地形共性的行星科学家的兴趣。
A string of volcanic features between Mono Lake and Mammoth Mountain is visible along the left side of this Landsat image. Known as the Mono-Inyo Craters , this chain of about three dozen lava domes, lava flows, and tephra rings formed within the past 10,000 years. Explosive eruptions in the area date back even further, but evidence of those older events is no longer apparent at the surface.
这张 Landsat 图像的左侧可以看到莫诺湖和猛犸山之间的一系列火山特征。这条由大约三打熔岩穹丘、熔岩流和火山灰环组成的链被称为莫诺-伊尼奥陨石坑，是在过去一万年里形成的。该地区的爆炸性喷发可以追溯到更早的时候，但这些较早事件的证据在地表上已不再明显。
Among the most recent activity in this chain, explosive eruptions formed Panum Crater near Mono Lake about 700 years ago. A strombolian eruption deposited a ring of pumice, ash, obsidian fragments, and other material around the vent. After that, a lava dome made of pumice and obsidian built up in the center, creating the concentric-circle pattern visible today.
在这一系列最近的活动中，大约 700 年前，莫诺湖附近的帕努姆火山口爆发了爆炸。斯特龙博利式喷发在喷口周围沉积了一圈浮石、火山灰、黑曜石碎片和其他物质。之后，中心形成了由浮石和黑曜石制成的熔岩圆顶，形成了今天可见的同心圆图案。
South of the Mono-Inyo Craters, Mammoth Mountain is perhaps best known for its ample skiable terrain, but it has a volcanic side, as well. The mountain is made up of at least 25 overlapping lava domes. Its last magmatic eruptions took place about 57,000 years ago, but steam-driven phreatic eruptions and other unrest have occurred much more recently.
猛犸山位于莫诺-因约陨石坑以南，也许以其广阔的滑雪地形而闻名，但它也有火山的一面。这座山由至少 25 个重叠的熔岩穹顶组成。它的最后一次岩浆喷发发生在大约 57,000 年前，但蒸汽驱动的潜水喷发和其他骚乱发生的时间要晚得多。
Scientists believe a magma intrusion beneath the mountain in 1989 set off a spate of seismicity and volcanic gas emissions . Venting of carbon dioxide gas has killed trees in the area, and the U.S. Geological Survey continues to monitor the mountain’s CO 2 emissions. Researchers have previously worked with NASA airborne remote sensing technology to measure ecosystem responses to elevated volcanic CO 2 around Mammoth Mountain. More recent projects have expanded these efforts to other volcanoes and incorporated satellite imagery to detect signs of gas emissions. These methods partly rely on changes observed in vegetation and could aid in earlier warnings of volcanic hazards.
科学家认为，1989 年岩浆侵入山下引发了大量地震活动和火山气体排放。二氧化碳气体的排放导致该地区的树木死亡，美国地质调查局继续监测这座山的 CO 2 排放量。研究人员此前曾利用 NASA 机载遥感技术来测量猛犸山周围生态系统对火山 CO 2 升高的反应。最近的项目已将这些工作扩展到其他火山，并结合卫星图像来检测气体排放的迹象。这些方法部分依赖于观察到的植被变化，有助于对火山灾害进行早期预警。
The most dramatic volcanism in the region, however, is far older. A massive eruption 760,000 years ago formed the Long Valley Caldera . This oval-shaped area, measuring 10 by 20 miles (16 by 32 kilometers), is bounded by snowy ridges, with Mammoth Mountain just off its southwest rim. Crowley Lake, a reservoir on the Owens River, drains the area to the southeast.
然而，该地区最引人注目的火山活动却历史悠久。 76万年前的一次大规模喷发形成了长谷火山口。这片椭圆形区域长 10 x 20 英里（16 x 32 公里），周围是白雪皑皑的山脊，猛犸山就位于其西南边缘。克劳利湖是欧文斯河上的一个水库，该地区的水流流向东南方。
The caldera was formed during a six-day-long eruption, during which 150 cubic miles (625 cubic kilometers) of material were ejected. (That’s about 20 times the amount that was spewed in the 1912 eruption of Novarupta , the largest on Earth in the 20th century.) As a result, the surface over the magma storage area subsided thousands of feet to create a vast depression. Scientists with NASA’s Goddard Instrument Field Team conducted research in the area in 2023 to better understand how similar massive eruptions on Mars and other planets and moons in our solar system may have altered their environments.
火山口是在为期六天的喷发过程中形成的，喷发期间喷射出 150 立方英里（625 立方公里）的物质。 （这大约是 1912 年诺瓦鲁普塔喷发喷发量的 20 倍，这是 20 世纪地球上最大的一次喷发。）结果，岩浆储存区的表面下沉了数千英尺，形成了一个巨大的凹陷。美国宇航局戈达德仪器现场团队的科学家于 2023 年在该地区进行了研究，以更好地了解火星以及太阳系其他行星和卫星上类似的大规模喷发可能如何改变其环境。
NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey . Story by Lindsey Doermann.
NASA 地球观测站图像由 Lauren Dauphin 使用美国地质调查局的陆地卫星数据拍摄。林赛·杜尔曼的故事。