Extensive eruptions of alkalic basalt from low-elevation fissures and vents on the southern flank of the dormant volcano, Cerro Evermann, accompanied the most recent phase of volcanic activity on Socorro Island, and created the Lomas Coloradas, a broad, gently sloping terrain comprising the southern part of the island. We obtained 14C ages of 4690 ± 270 BP (5000–5700 cal BP) and 5040 ± 460 BP (5300–6300 cal BP) from lacustrine deposits that occur within volcanic sequences of the lower Lomas Coloradas. Apparently, the sediments accumulated within a topographic depression between two scoria cones shortly after they formed. The lacustrine environment was destroyed when the cones were breached by headward erosion of adjacent stream drainages. This was followed by the eruption of a thin basaltic flow from fissures near the base of the northernmost cone. The flow moved downslope for a short distance and into the drainages that presently bound the study area on the east and west. The flow postdates development of the present drainage system and may be very recent. Our 14C data, along with historical accounts of volcanic activity over the last century, including submarine eruptions that occurred a few km west of Socorro in early 1993, underscore the high risk for explosive volcanism in this region and the need for a detailed volcanic hazards plan and seismic monitoring.

中文翻译：

---

墨西哥索科罗岛洛马斯科罗拉多地区火山序列中湖相沉积物的放射性碳年龄

休眠火山 Cerro Evermann 南侧的低海拔裂缝和喷口大量喷发碱性玄武岩，伴随着 Socorro 岛最近阶段的火山活动，形成了 Lomas Coloradas，这是一个宽阔、缓坡的地形，包括岛的南部。我们获得了14C 年龄为 4690 ± 270 BP (5000–5700 cal BP) 和 5040 ± 460 BP (5300–6300 cal BP)，来自发生在 Lomas Coloradas 下部火山序列中的湖泊沉积物。显然，沉积物在形成后不久就聚集在两个矿渣锥之间的地形凹陷中。当锥体被相邻河流排水系统的头部侵蚀破坏时，湖泊环境被破坏。随后从最北端锥体底部附近的裂缝喷发了稀薄的玄武岩流。水流沿着斜坡向下移动了一小段距离，并进入了目前界定研究区东西两侧的排水系统。流量落后于当前排水系统的发展，并且可能是最近的。我们的14C 数据以及上个世纪火山活动的历史记录，包括 1993 年初在索科罗以西几公里处发生的海底喷发，强调了该地区爆发性火山活动的高风险以及制定详细的火山灾害计划和地震监测。