Characterizing fault zones at Kilauea & Mauna Loa volcanoes by large-scale mapping of earthquake stress drops and focal mechanisms

描述基拉韦厄断层带的特征

基本信息

批准号：
1446543
负责人：
Robin Matoza
金额：
$ 22万
依托单位：
University of California-Santa Barbara
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2015
资助国家：
美国
起止时间：
2015-08-01 至 2021-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1446543&HistoricalAwards=false
关键词：
Characterizing fault zones Kilauea &amp

项目摘要

The analysis and interpretation of seismic sources from within Earth's mantle up to the surface plays a key role in understanding how volcanoes work. Hawaii Island is one of the most tectonically, volcanically, and seismically active regions on Earth. The USGS Hawaiian Volcano Observatory (HVO) operates a seismic network that has recorded over 260,000 earthquakes since 1986, but this rich dataset has not been fully exploited. This project supports collaboration between HVO, U.C. Santa Barbara, and U.C. San Diego to apply a number of new large-dataset processing methods to learn more about seismic activity on Hawaii and its relationship to faults and volcanoes. It also supports the educational program at U.C. Santa Barbara by providing funds for graduate student support. The results from this study are expected to yield a sharper and more comprehensive view of fault zone characteristics as well as generate public databases of high-resolution information on seismicity characteristics, suitable for other researchers in their studies of Hawaiian geology, tectonics, and volcanism. This research will lead to improved descriptions of seismicity and tectonics for Hawaii, which will improve our ability to monitor and characterize volcanic and earthquake hazards.By performing systematic and comprehensive analyses of seismicity recorded by HVO, this work will improve earthquake location precision, provide robust estimates of the patterns of earthquake stress drops, and compute more reliable earthquake focal mechanisms on Hawaii. Integrating these results will better characterize crustal and mantle fault zones and magma conduits in and around Kilauea and Mauna Loa volcanoes, and will help to resolve the relationships between seismicity, volcanic activity, and strain transients. Our results will address the following questions: (1) Relocated microearthquakes in Hawaii align along resolvable fault and conduit structures?what do these structures reveal about tectonic and volcanic processes? (2) What is the origin of recently discovered seismicity rings in Hawaii? (3) How do the stress drops of Hawaiian earthquakes compare to other regions? Are there variations in earthquake stress drops that can be used to characterize stress field heterogeneity and identify regions of stress concentration? (4) Can focal mechanisms be improved for small earthquakes in Hawaii and what do they reveal about the faulting process and stress state? (5) Can repeating earthquakes with nearly identical waveforms be used to resolve temporal variations in seismic velocity associated with tectonic and volcanic activity? (6) How do the characteristics of long-period (LP, 0.5-5 Hz) seismicity at Kilauea volcano relate to redistributions of magma and stress within its magma supply system?

从地球内到地面的地震来源的分析和解释在理解火山的工作方式方面起着关键作用。夏威夷岛是地球上最构造，火山和地震活跃地区的岛屿之一。 USGS夏威夷火山天文台（HVO）运营着一个地震网络，自1986年以来一直记录了超过260,000台地震，但该丰富的数据集并未得到充分利用。该项目支持U.C. HVO之间的合作圣塔芭芭拉（Santa Barbara）和U.C.圣地亚哥采用多种新的大型处理方法，以了解有关夏威夷地震活动及其与断层和火山的关系的更多信息。它还支持U.C.的教育计划圣塔芭芭拉（Santa Barbara）提供资金来研究生支持。预计这项研究的结果将对断层区特征产生更清晰，更全面的看法，并生成有关地震性特征的高分辨率信息的公共数据库，适用于其他研究人员在夏威夷地质，构造和火山学研究中。这项研究将导致对夏威夷的地震性和构造学的描述，这将提高我们监控和表征火山和地震危害的能力。通过执行HVO记录的系统和全面的地震性分析，这项工作将改善地震位置的精度，改善对地震压力降低的强大估算，并在地震范围内进行越来越多的范围。整合这些结果将更好地表征地壳和地幔断层区域和岩浆导管，及其周边地区和Mauna Loa火山，并将有助于解决地震性，火山活动和应变瞬变之间的关系。我们的结果将解决以下问题：（1）夏威夷沿夏威夷沿可分离的断层和导管结构对齐的微地Quake？这些结构揭示了有关构造和火山过程的什么？（2）最近发现的地震环在夏威夷的起源是什么？（3）与其他地区相比，夏威夷地震的压力下降如何？地震应力下降的变化是否可用于表征应力场异质性并鉴定应力浓度的区域？（4）可以改善夏威夷小地震的焦点机制，它们揭示了断层过程和压力状态的什么？（5）可以使用几乎相同波形的重复地震来解决与构造和火山活性相关的地震速度的时间变化？（6）Kilauea火山的长期（LP，0.5-5 Hz）地震性的特征与岩浆供应系统中的岩浆和压力的重新分布有关？