The Seismic Record最新文献_第6页

Multi-Event Explosive Seismic Source for the 2022 Mw 6.3 Hunga Tonga Submarine Volcanic Eruption 2022 Mw 6.3 Hunga Tonga海底火山喷发的多事件爆炸震源

The Seismic Record Pub Date : 2022-10-01 DOI: 10.1785/0320220027

J. Thurin, C. Tape, R. Modrak

引用次数: 9

Rupture Directivity of the 2021 ML 2.2 Gwangyang, Korea, Microearthquake: Toward Resolving High-Resolution Rupture Process of a Small Earthquake 韩国光阳，2021 ML 2.2微地震的破裂方向:小地震的高分辨率破裂过程

The Seismic Record Pub Date : 2022-10-01 DOI: 10.1785/0320220030

Minyoung Seo, Won-Young Kim, Younghee Kim

{"title":"Rupture Directivity of the 2021 ML 2.2 Gwangyang, Korea, Microearthquake: Toward Resolving High-Resolution Rupture Process of a Small Earthquake","authors":"Minyoung Seo, Won-Young Kim, Younghee Kim","doi":"10.1785/0320220030","DOIUrl":"https://doi.org/10.1785/0320220030","url":null,"abstract":"\u0000 Moderate-to-large earthquakes (M>6) frequently show clear rupture directivity. Recent studies revealed that a substantial percentage of small-sized earthquakes (M<∼5) display rupture directivity as well, owing to enhanced seismic monitoring. Is rupture directivity a common feature for earthquakes of all sizes? In this study, we investigated the rupture directivity of the 27 August 2021 ML 2.2 Gwangyang microearthquake that occurred at the southern tip of the Korean Peninsula by utilizing data from a recently expanded dense seismic network. The mainshock had two foreshocks and three aftershocks, which enabled us to define the fault plane from precise relative event locations and a well-constrained focal mechanism. Analysis of apparent source time functions obtained with the empirical Green’s function technique reveals that the mainshock ruptured unilaterally toward the east. A detailed analysis of the source pulse leaving the focal sphere in 3D indicates that rupture directivity is consistent with the fault geometry and slip direction. Our study demonstrates that we can resolve rupture directivity of unilaterally rupturing microearthquakes (M<∼3) given adequate azimuthal coverage, and that this will lead to an improved understanding of the seismogenic processes in regions of low seismicity worldwide.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134507865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Variability in the Natural Frequencies of a Nine-Story Concrete Building from Seconds to Decades 从秒到几十年九层混凝土建筑的自然频率变化

The Seismic Record Pub Date : 2022-10-01 DOI: 10.1785/0320220032

E. Williams, T. Heaton, Z. Zhan, Valère Lambert

{"title":"Variability in the Natural Frequencies of a Nine-Story Concrete Building from Seconds to Decades","authors":"E. Williams, T. Heaton, Z. Zhan, Valère Lambert","doi":"10.1785/0320220032","DOIUrl":"https://doi.org/10.1785/0320220032","url":null,"abstract":"\u0000 Since 2001, the Southern California Seismic Network has archived continuous waveform data from strong-motion station CI.MIK in Caltech Hall (formerly Millikan Library)—a nine-story reinforced concrete building. Simple spectral analysis of this 20 yr record reveals that the building’s fundamental frequencies have increased gradually by 5.1% (east–west) and 2.3% (north–south), with larger long-term variability up to 9.7% (east–west) and 4.4% (north–south). This finding is unexpected, as previous analysis of forced vibration tests and strong-motion records has shown that between 1968 and 2003 the fundamental frequencies decreased by 22% (east–west) and 12% (north–south), largely attributed to minor structural damage and soil–structure system changes from major earthquakes. Today, the building’s apparent structural stiffness is comparable to what it was in 1986, before the Whittier Narrows earthquake. Using data from earthquakes and forced vibrations, we also document the building’s nonlinear dynamic elasticity, which is characterized by a rapid softening (decrease in apparent frequencies) at the onset of strong motion, followed by a slower, log–linear recovery trend over the scale of minutes. This nonlinear behavior does not appear to have changed with time.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116537081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Evidence of Active Quaternary Deformation on the Great Valley Fault System near Winters, Northern California 北加州温特斯附近大峡谷断裂系统第四纪活跃变形的证据

The Seismic Record Pub Date : 2022-10-01 DOI: 10.1785/0320220029

Charles C. Trexler, A. Morelan, R. Catchings, M. Goldman, J. Willard

{"title":"Evidence of Active Quaternary Deformation on the Great Valley Fault System near Winters, Northern California","authors":"Charles C. Trexler, A. Morelan, R. Catchings, M. Goldman, J. Willard","doi":"10.1785/0320220029","DOIUrl":"https://doi.org/10.1785/0320220029","url":null,"abstract":"\u0000 The Great Valley fault system defines the tectonic boundary between the Coast Ranges and the Central Valley in California, is active throughout the Quaternary, and has been the source of several significant (M > 6) historic earthquakes, including the 1983 M 6.5 Coalinga earthquake and the 1892 Vacaville–Winters earthquake sequence. However, the locations and geometries of individual faults in the Great Valley fault system are poorly constrained, and fault slip rates and paleoearthquake chronology are largely unknown. Here, we report geomorphic and subsurface geophysical evidence of surface-deforming displacement on a strand of the Great Valley fault system west of Winters, California. Detailed geomorphic mapping and a high-resolution seismic reflection and tomography survey along an ∼800 m profile across the Bigelow Hills document a fault, which we call the West Winters strand of the Great Valley fault system, with apparent east side-up displacement of surficial geologic units. These data together suggest that the West Winters strand is active in the latest Quaternary. Together with local reports from the time, this raises the possibility that the West Winters strand may have ruptured and deformed the surface during the 1892 M 6 Vacaville–Winters earthquake sequence. Future earthquakes with vertical displacement on this and Great Valley fault system structures could have significant hazard implications, given the region’s low relief and the presence of major water conveyance infrastructure.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"95 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129202223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Rotational Components of Normal Modes Measured at a Natural Sandstone Tower (Kane Springs Canyon, Utah, U.S.A.) 天然砂岩塔(美国犹他州凯恩泉峡谷)正模态旋转分量测量

The Seismic Record Pub Date : 2022-10-01 DOI: 10.1785/0320220035

A. Dzubay, J. Moore, R. Finnegan, Erin K. Jensen, Paul R. Geimer, K. Koper

{"title":"Rotational Components of Normal Modes Measured at a Natural Sandstone Tower (Kane Springs Canyon, Utah, U.S.A.)","authors":"A. Dzubay, J. Moore, R. Finnegan, Erin K. Jensen, Paul R. Geimer, K. Koper","doi":"10.1785/0320220035","DOIUrl":"https://doi.org/10.1785/0320220035","url":null,"abstract":"\u0000 Modal analysis of freestanding rock formations is crucial for evaluating their vibrational response to external stimuli, aiding accurate assessment of associated geohazards. Whereas conventional seismometers can be used to measure the translational components of normal modes, recent advances in rotational seismometer technology now allow direct measurement of the rotational components. We deployed a portable, three-component rotational seismometer for a short-duration experiment on a 36 m high sandstone tower located near Moab, Utah, in addition to conducting modal analysis using conventional seismic data and numerical modeling. Spectral analysis of rotation rate data resolved the first three natural frequencies of the tower (2.1, 3.1, and 5.9 Hz), and polarization analysis revealed the orientations of the rotation axes. Modal rotations were the strongest for the first two eigenmodes, which are mutually perpendicular, full-height bending modes with horizontal axes of rotation. The third mode is torsional with rotation about a subvertical axis. Measured natural frequencies and the orientations of displacements and rotation axes match our numerical models closely for these first three modes. In situ measurements of modal rotations are valuable at remote field sites with limited access, and contribute to an improved understanding of modal deformation, material properties, and landform response to vibration stimuli.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123901910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ground-Motion Evaluation of Hybrid Seismic Velocity Models 混合地震速度模型的地震动评价

The Seismic Record Pub Date : 2022-07-01 DOI: 10.1785/0320220022

R. Ajala, P. Persaud

{"title":"Ground-Motion Evaluation of Hybrid Seismic Velocity Models","authors":"R. Ajala, P. Persaud","doi":"10.1785/0320220022","DOIUrl":"https://doi.org/10.1785/0320220022","url":null,"abstract":"\u0000 Cost-effective strategies for enhancing seismic velocity models are an active research topic. The recently developed hybridization technique shows promise in improving models used for deterministic earthquake hazard evaluation. We augment the results of Ajala and Persaud (2021) by exploring other hybrid models generated using 13 sets of embedding parameters—taper widths and subvolumes—and summarize their effect on waveform predictions up to a minimum period of 2 s. Our results introduce the notion of compatibility as a consideration by showing that the same basin models embedded into two different regional models can produce notably different outcomes. In contrast to most of our hybrid Harvard models that produce better matching ground motions, only one of the hybrid models generated using the Southern California Earthquake Center model as a regional model gives a closer match to the waveforms. Similar results are obtained at higher frequencies; however, improvements due to hybridization are reduced. A potential explanation for these results may be the limited high spatial frequencies in the travel time tomography basin models and the >5–6 s wavefield-dominated adjoint regional models. Although the strongly tapered compatible hybrid models tend to produce better results, we find instances of improvements even with merging artifacts.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127887529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Ground Motion Amplification at Natural Rock Arches in the Colorado Plateau 科罗拉多高原天然岩石拱的地震动放大

The Seismic Record Pub Date : 2022-07-01 DOI: 10.1785/0320220017

R. Finnegan, J. Moore, Paul R. Geimer, E. Bessette-Kirton, A. Dzubay

{"title":"Ground Motion Amplification at Natural Rock Arches in the Colorado Plateau","authors":"R. Finnegan, J. Moore, Paul R. Geimer, E. Bessette-Kirton, A. Dzubay","doi":"10.1785/0320220017","DOIUrl":"https://doi.org/10.1785/0320220017","url":null,"abstract":"\u0000 Thousands of rock arches are situated within the central Colorado Plateau—a region experiencing small- to moderate-magnitude contemporary seismicity. Recent anthropogenic activity has substantially increased the seismicity rate in some areas, raising questions about the potential for vibration damage of natural arches, many of which have high cultural value. However, predictions of the vibration response and potential for damage at a given site are limited by a lack of data describing spectral amplification of ground motion on these landforms. We analyzed 13 sandstone arches in Utah, computing site-to-reference spectral amplitude ratios from continuous ambient seismic data, and compared these to spectral ratios during earthquakes and teleseismic activity. We found peak ground velocities on arches at their dominant natural modes (in the range of 2–20 Hz) are ∼20–180 times the velocity on adjacent bedrock, due to amplification arising from slender geometry and low modal damping (0.8%–2.7%). Ambient spectral ratios are generally 1.2–2.0 times the coseismic spectral ratios. Because arches experience highly amplified ground motion, the range of earthquakes considered potentially damaging may need to be revised to include lower-magnitude events. Our results have implications for conservation management of these and other culturally valuable landforms.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133213516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Waveform Features Strongly Control Subcrater Classification Performance for a Large, Labeled Volcano Infrasound Dataset 波形特征对大型标记火山次声数据集的亚火山口分类性能有很强的控制作用

The Seismic Record Pub Date : 2022-07-01 DOI: 10.1785/0320220019

L. Toney, D. Fee, Alex J. C. Witsil, R. Matoza

引用次数: 2

Earthquakes in the Shadows: Why Aftershocks Occur at Surprising Locations 阴影中的地震:为什么余震发生在令人惊讶的地方

The Seismic Record Pub Date : 2022-07-01 DOI: 10.1785/0320220023

J. Hardebeck, R. Harris

{"title":"Earthquakes in the Shadows: Why Aftershocks Occur at Surprising Locations","authors":"J. Hardebeck, R. Harris","doi":"10.1785/0320220023","DOIUrl":"https://doi.org/10.1785/0320220023","url":null,"abstract":"\u0000 For decades there has been a debate about the relative effects of dynamic versus static stress triggering of aftershocks. According to the static Coulomb stress change hypothesis, aftershocks should not occur in stress shadows—regions where static Coulomb stress has been reduced. We show that static stress shadows substantially influence aftershock occurrence following three M ≥ 7 California mainshocks. Within the modeled static Coulomb stress shadows, the aftershock rate is an order of magnitude lower than in the modeled increase regions. However, the earthquake rate in the stress shadows does not decrease below the background rate, as predicted by Coulomb stress change models. Aftershocks in the stress shadows exhibit different spatial–temporal characteristics from aftershocks in the stress increase regions. The aftershock rate in the stress shadows decays as a power law with distance from the mainshock, consistent with a simple model of dynamic stress triggering. These aftershocks begin with a burst of activity during the first few days after the mainshock, also consistent with dynamic stress triggering. Our interpretation is that aftershock sequences are the combined result of static and dynamic stress triggering, with an estimated ∼34% of aftershocks due to dynamic triggering and ∼66% due to static triggering.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114269147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

The Kalaotoa Fault: A Newly Identified Fault that Generated the Mw 7.3 Flores Sea Earthquake 卡拉托亚断层:新发现的导致弗洛雷斯海7.3级地震的断层

The Seismic Record Pub Date : 2022-07-01 DOI: 10.1785/0320220015

P. Supendi, N. Rawlinson, B. S. Prayitno, S. Widiyantoro, A. Simanjuntak, K. Palgunadi, Andri Kurniawan, G. Marliyani, A. Nugraha, D. Daryono, S. D. Anugrah, Iman Fatchurochman, M. T. Gunawan, M. Sadly, S. Adi, D. Karnawati, A. Arimuko

{"title":"The Kalaotoa Fault: A Newly Identified Fault that Generated the Mw 7.3 Flores Sea Earthquake","authors":"P. Supendi, N. Rawlinson, B. S. Prayitno, S. Widiyantoro, A. Simanjuntak, K. Palgunadi, Andri Kurniawan, G. Marliyani, A. Nugraha, D. Daryono, S. D. Anugrah, Iman Fatchurochman, M. T. Gunawan, M. Sadly, S. Adi, D. Karnawati, A. Arimuko","doi":"10.1785/0320220015","DOIUrl":"https://doi.org/10.1785/0320220015","url":null,"abstract":"\u0000 We reveal the existence of a previously unknown fault that generated the Mw 7.3 Flores Sea earthquake, which occurred on 14 December 2021, approximately 100 km to the north of Flores Island, in one of the most complex tectonic settings in Indonesia. We use a double-difference method to relocate the hypocenters of the mainshock and aftershocks, determine focal mechanisms using waveform inversion, and then analyze stress changes to estimate the fault type and stress transfer. Our relocated hypocenters show that this earthquake sequence ruptured on at least three segments: the source mechanism of the mainshock exhibits dextral strike-slip motion (strike N72°W and dip 78° NE) on a west–east-trending fault that we call the Kalaotoa fault, whereas rupture of the other two segments located to the west and east of the mainshock (striking west-northwest and southeast, respectively) may have been triggered by this earthquake. The Coulomb stress change imparted by the rupture of these segments on nearby faults is investigated, with a focus on regions that experience a stress increase with few associated aftershocks. Of particular interest are stress increases on the central back-arc thrust just north of Flores and the north–south-striking Selayar fault in the northwest of our study region, both of which may be at increased risk of failure as a result of this unusual earthquake sequence.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116117412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4