RUI: The Owens River as a Tiltmeter for Long Valley Caldera,California

自1979年以来，长谷破火山口的复活圆顶， 加州的水位上升了50多厘米， 注入0.2立方千米的岩浆。 地震（6.0） 伴随着最初的隆起;美国地质勘探局警告说， 喷发活动 欧文斯河的洪泛区证据表明， 目前的上涨是长期通胀的一部分，可能总计15- 35米。 大部分的下游显示出两个最近的平行 曲流带（相距200- 300米），曲流波长相似， 幅度，但年龄不等。 年纪越大，总是越接近 圆顶和30-60厘米高海拔，现在进行了不足 流，被遗弃。 新的下水道由 撕脱，显然是由隆起引起的。 有四个年长的， 存在独立的曲流带，表明有两个隆起旋回 而沉降可能先于当前的通货膨胀。 拟议的研究将涉及以下方面 调查事务所 (1)我们将进行一系列详细的水准测量 垂直于山谷轴线的测量，以确定 河间面作为穹状隆起的估计，（2）我们将 确定几个曲流带牛轭沉积物的年龄 结合火山灰年代学和14 C（森林火灾 木炭和可能的泥炭），以确定时间的长度， 河流占据了每一个曲流带。 这些年龄会有所帮助 定义了隆起和沉降的时间， 河道迁移和火山喷发之间可能存在的相关性 在Inyo和Mono Crater领域的活动。 (3)我们将比较 河流的历史和现代照片，以确定最近的 通道迁移率，并将其与本地度进行比较 在水准测量中确定的漫滩倾斜。 对复活的圆顶近代史的理解 是加州猛犸湖居民最关心的问题。 的 拟议的调查为本科生提供了一个优秀的 有机会在现场和实验室进行研究， 这是一个重要的火山活动例子，也是一个有趣的 河流地貌学中的现象。

Since 1979, the resurgent dome of Long Valley caldera, California has risen more than 50 cm apparently due to the injection of 0.2 km3 of magma at depths. Several earthquakes (6.0) accompanied the initial uplift; the USGS has warned of possible eruptive activity. Floodplain evidence from the Owens River suggests that the current uplift is part of a long term inflation that may total 15- 35 meters. Most of the lower river displays two recent parallel meander belts (200-300m apart), similar in meander wavelength and amplitude, but unequal in age. The older, invariably closer to the dome and 30-60 cm higher in elevation, now carries an underfit stream and is being abandoned. The new lower channel formed by avulsion, apparently triggered by uplift. As many as four older, separate meander belts exist and suggest that two cycles of uplift and subsidence may have preceded the current inflation. The proposed research would involve the following investigations. (1) We will make a series of detailed leveling surveys perpendicular to the valley axis to define the pitch of the interfluvial surface as an estimate of domal uplift, (2) We will determine ages for oxbow sediments from the several meander belts using a combination of tephrochronology and 14C (forest fire charcoal and possible peat) to define the length of time that the river occupied each of these meander belts. These ages will help define both the times of uplift and subsidence as well as the possible correlation between river channel migrations and eruptive activity in the Inyo and Mono Crater fields. (3) We will compare historic and modern photographs of the river to determine recent rates of channel migration and compare them with the local degree of floodplain tilting determined in the leveling surveys. An understanding of the recent history of the resurgent dome is of central concern to residents of Mammoth Lakes, CA. The proposed investigation offers undergraduate students an excellent opportunity to study both in the field and in the laboratory an important example of silicic volcanism, as well as an interesting phenomenon in fluvial geomorphology.