The Seismic Record最新文献_第5页

Rupture Directivity of the 25 October 2022 Mw 5.1 Alum Rock Earthquake 2022年10月25日5.1 Mw明矾岩地震的破裂方向

The Seismic Record Pub Date : 2023-04-01 DOI: 10.1785/0320230013

E. Hirakawa, G. Parker, A. Baltay, T. Hanks

引用次数: 1

The 2023 Southeast Türkiye Seismic Sequence: Rupture of a Complex Fault Network 2023东南<s:1> rkiye地震序列:一个复杂断层网的破裂

The Seismic Record Pub Date : 2023-04-01 DOI: 10.1785/0320230008

G. Petersen, P. Büyükakpınar, Felipe Orlando Vera Sanhueza, M. Metz, S. Cesca, K. Akbayram, J. Saul, T. Dahm

{"title":"The 2023 Southeast Türkiye Seismic Sequence: Rupture of a Complex Fault Network","authors":"G. Petersen, P. Büyükakpınar, Felipe Orlando Vera Sanhueza, M. Metz, S. Cesca, K. Akbayram, J. Saul, T. Dahm","doi":"10.1785/0320230008","DOIUrl":"https://doi.org/10.1785/0320230008","url":null,"abstract":"\u0000 On 6 February 2023, southeastern Türkiye experienced two Mw 7.7 and 7.6 earthquakes. The earthquake sequence caused widespread damage and tens of thousands of casualties in Türkiye and Syria. We analyze mainshocks and aftershocks, combining complementary source characterization techniques, relying on local, regional, and teleseismic data. Backprojection analysis and finite source inversion for the mainshocks resolve coseismic slip, rupture length, and propagation mode along the main faults, whereas centroid moment tensor inversion for 221 aftershocks resolves details of the fault network. The first mainshock nucleated on a splay fault and activated the neighboring East Anatolian fault zone (EAFZ). It ruptured bilaterally along ∼500 km first toward northeast and later to south-southwest on multiple, previously partly dormant fault segments. The second mainshock ruptured the east–west-oriented Sürgü-Misis fault zone (SMFZ), reaching a slip of 7 m. The analysis of aftershocks with heterogeneous moment tensors retrospectively reconstructs rupture details. Along the main strand of the EAFZ, they map the geometry of different segments in unprecedented detail, whereas along the SMFZ they illuminate the geometry and behavior of large structures for the first time. Our work sheds light on multiple aspects of rupture evolution and provides new insights into the devastating earthquake sequence.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123336743","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: 10

Fiber-Optic Airplane Seismology on the Northeast Greenland Ice Stream 格陵兰岛东北部冰流的光纤飞机地震学

The Seismic Record Pub Date : 2023-04-01 DOI: 10.1785/0320230004

A. Fichtner, C. Hofstede, Brian L. N. Kennett, Niels F. Nymand, Mikkel L. Lauritzen, D. Zigone, O. Eisen

引用次数: 4

On the Importance of Using Directional Information in the Search for Lower Mantle Reflectors 论利用定向信息寻找下地幔反射体的重要性

The Seismic Record Pub Date : 2023-04-01 DOI: 10.1785/0320220038

F. Rochira, C. Thomas

{"title":"On the Importance of Using Directional Information in the Search for Lower Mantle Reflectors","authors":"F. Rochira, C. Thomas","doi":"10.1785/0320220038","DOIUrl":"https://doi.org/10.1785/0320220038","url":null,"abstract":"\u0000 The SS precursor signals are a powerful tool for mapping topography of mantle discontinuities, which are sensitive to the thermal and compositional structure of the mantle. The depth of mantle discontinuities is usually estimated using the differential travel time between the main arrival and its precursor. However, this method ignores potential travel path deviations that influence the travel time of precursor signals. Here, we use an approach that considers directivity information as well as travel-time measurements. Applying seismic array techniques, we measure slowness, back azimuth, and travel time of the signals, and use this information to backproject to the point of reflection. In our test dataset, we observe deviations from the predicted values in slowness and back azimuth in the range of 0.1–2.3 s/° and 1–20°, respectively. These values lead to reflection locations that can differ considerably from theoretical reflection points calculated with great circle plane paths as well as depths different from the depth calculated for in-plane propagation, with differences up to ∼150 km. Our results indicate that the travel-path deviations should be considered to avoid misinterpretation of mantle discontinuities and potentially reduce previously observed scatter in discontinuity depth.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129384314","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

“Aftershock Faults” and What They Could Mean for Seismic Hazard Assessment “余震断层”及其对地震危险性评估的意义

The Seismic Record Pub Date : 2023-01-01 DOI: 10.1785/0320220036

T. Parsons, E. Geist, S. E. Parsons

{"title":"“Aftershock Faults” and What They Could Mean for Seismic Hazard Assessment","authors":"T. Parsons, E. Geist, S. E. Parsons","doi":"10.1785/0320220036","DOIUrl":"https://doi.org/10.1785/0320220036","url":null,"abstract":"\u0000 We study stress-loading mechanisms for the California faults used in rupture forecasts. Stress accumulation drives earthquakes, and that accumulation mechanism governs recurrence. Most moment release in California occurs because of relative motion between the Pacific plate and the Sierra Nevada block; we calculate relative motion directions at fault centers and compare with fault displacement directions. Dot products between these vectors reveal that some displacement directions are poorly aligned with plate motions. We displace a 3D finite-element model according to relative motions and resolve stress tensors onto defined fault surfaces, which reveal that poorly aligned faults receive no tectonic loading. Because these faults are known to be active, we search for other loading mechanisms. We find that nearly all faults with no tectonic loading show increase in stress caused by slip on the San Andreas fault, according to an elastic dislocation model. Globally, faults that receive a sudden stress change respond with triggered earthquakes that obey an Omori law rate decay with time. We therefore term this class of faults as “aftershock faults.” These faults release ∼4% of the moment release in California, have ∼0.1%–5% probability of M 6.7 earthquakes in 30 yr, and have a 0.001%–1% 30 yr M 7.7 probability range.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121058035","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

Point-Source Decay of Ground-Motion Amplitudes at <10 km <10公里处地震动振幅的点源衰减

The Seismic Record Pub Date : 2023-01-01 DOI: 10.1785/0320220040

G. Atkinson, G. Viegas

引用次数: 0

Fault Roughness at Seismogenic Depths and Links to Earthquake Behavior 发震深度的断层粗糙度及其与地震行为的联系

The Seismic Record Pub Date : 2023-01-01 DOI: 10.1785/0320220043

E. Cochran, M. Page, N. J. van der Elst, Z. Ross, D. Trugman

{"title":"Fault Roughness at Seismogenic Depths and Links to Earthquake Behavior","authors":"E. Cochran, M. Page, N. J. van der Elst, Z. Ross, D. Trugman","doi":"10.1785/0320220043","DOIUrl":"https://doi.org/10.1785/0320220043","url":null,"abstract":"\u0000 Fault geometry affects the initiation, propagation, and cessation of earthquake rupture, as well as, potentially, the statistical behavior of earthquake sequences. We analyze 18,250 (−0.27 < M < 4.4) earthquakes of the 2016–2019 Cahuilla, California, swarm and, for the first time, use these high-resolution earthquake locations to map, in detail, the roughness across an active fault surface at depth. We find that the strike-slip fault is 50% rougher in the slip-perpendicular direction than parallel to slip. 3D mapping of fault roughness at seismogenic depths suggests that roughness varies by a factor of 8 for length scales of 1 km. We observe that the largest earthquake (M 4.4) occurred where there is significant fault complexity and the highest measured roughness. We also find that b-values are weakly positively correlated with fault roughness. Following the largest earthquake, we observe a distinct population of earthquakes with comparatively low b-values occurring in an area of high roughness within the rupture area of the M 4.4 earthquake. Finally, we measure roughness at multiple scales and find that the fault is self-affine with a Hurst exponent of 0.52, consistent with a Brownian surface.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125550885","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

Utilization of Crowdsourced Felt Reports to Distinguish High-Impact from Low-Impact Earthquakes Globally within Minutes of an Event 利用众包感知报告在事件发生后几分钟内区分全球高影响地震和低影响地震

The Seismic Record Pub Date : 2023-01-01 DOI: 10.1785/0320220039

H. Lilienkamp, R. Bossu, F. Cotton, F. Finazzi, M. Landès, G. Weatherill, S. von Specht

{"title":"Utilization of Crowdsourced Felt Reports to Distinguish High-Impact from Low-Impact Earthquakes Globally within Minutes of an Event","authors":"H. Lilienkamp, R. Bossu, F. Cotton, F. Finazzi, M. Landès, G. Weatherill, S. von Specht","doi":"10.1785/0320220039","DOIUrl":"https://doi.org/10.1785/0320220039","url":null,"abstract":"\u0000 Rapid assessment of an earthquake’s impact on the affected society is a crucial step in the early phase of disaster management, navigating the need for further emergency response measures. We demonstrate that felt reports collected via the LastQuake service of the European Mediterranean Seismological Center can be utilized to rapidly estimate the probability of a felt earthquake being high impact rather than low impact on a global scale. Our data-driven, transparent, and reproducible method utilizing Bayes’ theorem and kernel density estimation provides results within 10 min for 393 felt events in 2021. Although a separation of high- and low-impact events remains challenging, the correct and unambiguous assessment of a large portion of low-impact events is a key strength of our approach. We consider our method as an inexpensive addition to the pool of earthquake impact assessment tools, one that is fully independent of seismic data and can be utilized in many populated areas on the planet. Although practical deployment of our method remains an open task, we demonstrate the potential to improve disaster management in regions that currently lack expensive seismic instrumentation.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129912778","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: 1

P/SV Amplitude Ratios of Shallow Isotropic Explosions and Earthquakes Could Be Indistinguishable at Local Distances: Insights from Single-Station Waveform Simulations 浅层各向同性爆炸和地震的P/SV振幅比在局部距离上无法区分:来自单站波形模拟的见解

The Seismic Record Pub Date : 2023-01-01 DOI: 10.1785/0320220044

Miao Zhang

{"title":"P/SV Amplitude Ratios of Shallow Isotropic Explosions and Earthquakes Could Be Indistinguishable at Local Distances: Insights from Single-Station Waveform Simulations","authors":"Miao Zhang","doi":"10.1785/0320220044","DOIUrl":"https://doi.org/10.1785/0320220044","url":null,"abstract":"\u0000 Shear waves play a key role in seismic discrimination between explosions and earthquakes due to their different source mechanisms. However, shear waves are often observed in field explosions with unexpectedly large amplitude, and their generation mechanism is still a significant unresolved question in seismology. Many explanations have been proposed, including the asymmetry of explosive sources, and heterogeneity and/or anisotropy of the Earth’s subsurface. However, it has not been well understood whether source or velocity structure can independently and sufficiently explain the shear waves generated by explosions. Theoretically, tangential SH waves can be converted and scattered from vertical and radial SV waves due to anisotropy and heterogeneity. Thus, it is essential to understand the generation of SV waves by explosions. In this study, we utilize the frequency–wavenumber algorithm and 1D layered velocity models to simulate waveforms of isotropic explosions and double-couple earthquakes at local distances (<20 km). Our results suggest that explosions and earthquakes may generate comparable SV waves if both occurred within a near-surface velocity gradient zone. The earliest SV waves by explosions appear to originate from the near-source region. It implies that P/SV amplitude ratios of explosions and earthquakes could be indistinguishable under certain circumstances.","PeriodicalId":273018,"journal":{"name":"The Seismic Record","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115426501","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: 1

Investigations of Ambient Noise Velocity Variations in a Region of Induced Seismicity near Greeley, Colorado 科罗拉多州格里利附近诱发地震活动区域的环境噪声速度变化研究

The Seismic Record Pub Date : 2023-01-01 DOI: 10.1785/0320220033

Tom Clifford, A. Sheehan, M. Moschetti

引用次数: 0