It is complicated to model the acoustic field in stratified ocean for airborne aircraft, due to high speed of the source and acoustic transmission across the air-water interface. The wavenumber integration representation given by Schmidt and Kuperman can be used to model the temporal received signal for a moving source in stratified media. However, it requires intensive computation for calculating two-dimensional integrals at each time sampling point. In this paper, a faster calculation method is presented, and the computation cost for the integrals can be reduced obviously. The acoustic fields in both shallow water and deep-sea environments were computed using this method with rapidly moving airborne source. When the source moves through a static receiver, an approximation of one-dimensional wave-number integration can be obtained by stationary phase method
Abstract The Qilian–Haiyuan fault zone in the northeastern Tibetan Plateau has been the source of strong earthquakes in the region. In its middle segment, the Jinqianghe fault is an important active fault within the Tianzhu seismic gap; however, little is known about its slip behavior. To present a new horizontal displacement distribution along this fault, we used WorldView‐2 stereo pairs and unmanned aerial vehicle‐based photogrammetry to construct digital elevation models to obtain a detailed tectono‐geomorphic interpretation and geomorphic offsets. The offset marker measurements yielded 135 geomorphic displacements and 8 offset clusters. Radiocarbon dating was used to establish the regional age sequence of the geomorphic units in offset fluvial terraces at four study sites. The displacements and ages linked the offset clusters with the geomorphic unit sequence; the Holocene strike‐slip rate of the Jinqianghe fault was estimated to 4.8–5.6 mm/a at ∼4–12 ka and 2.9–4.7 mm/a from ∼4 ka. Three recent earthquakes (with a recurrence interval of ∼1000 years) represent an active seismic period, revealing the potential seismic hazard along this fault because it has not ruptured in the last 1500 years.
Contents of this file Text S1 to S3 Figures S1 to S3 Tables S1 to S4 Additional Supporting Information (Files uploaded separately) Text S1 Demagnetization and tests Text S2 Anisotropy of magnetic susceptibility (AMS) analyses Text S3 Detrital Zircons U-Pb Ages test Figure S1. Anhua sampling section. Figure S2. Photographs of the sampled Anhua-Huicheng basin section. Figure S3 Orthogonal (Zijderveld) vector plots of the representative thermal demagnetization behaviors of specimens from the Anhua section. Figure S4 Equal-area plots of accepted ChRMs (185 sites) from the Anhua section in (a) geographic and (b) tilt-corrected coordinates. Figure S5 AMS data. (a) Equal-area, lower-hemisphere projection of anisotropy of the maximum (blue squares), medium (green triangles) and minimum (pink circles) susceptibility axes in stratigraphic coordinates. (b) PJ–T (corrected degrees of anisotropy vs. shape parameter). (c) Flinn diagram. Table S1. Main characteristics and interpretations of major sedimentary facies in this study. Table S2. Fossils were discovered along the West Qinling Belt. Table S3. Zircon U-Pb geochronological analyses. Table S4. Quantitative comparison of age distributions for the Anhua basin (Z1&Z2; Z3&Z4).
Growth of the Tibetan Plateau, Earth’s broadest and highest elevation collisional system, shapes orographic barriers, reorganizes drainage networks, and influences surface erosion and sediment delivery, whose changes in space and provenance feed back to intracontinental tectonic processes. Studies of interior basins within the northern Tibetan Plateau provide new sediment accumulation, provenance, paleodrainage, and deformation timing data that enable a reconstruction of the far-field tectono-geomorphic evolution of the rising Tibetan Plateau. Along the northern plateau margin, topographic growth in the West Qinling Belt is inferred to have initiated in the Eocene, nearly coeval with the India-Asia collision, as well as in the late Miocene. However, geological knowledge about the intervening period remains at present enigmatic, and the kinematics and dynamics are uncertain. This study presents a multidisciplinary data set from the intermontane Anhua-Huicheng Basin (AHB; Gansu Province, China) to fill this gap. Magnetostratigraphic dating, regional mapping, and sedimentological analysis imply that contractional deformation and thrust-top basin systems formed within the West Qinling Belt in the Oligocene (not later than ca. 24 Ma). A combination of observations including paleocurrent changes, detrital zircon U-Pb age variations, and appearance of growth strata along the Anhua-Huicheng Basin reveal the rapid uplift of the West Qinling Belt at ca. 15 Ma. Sedimentation in the intermontane basins ended after the late Miocene (ca. 8 Ma), when the region experienced intrabasinal deformation, uplift, and erosion with the establishment of an external drainage system. Since the late Miocene, the growth of the West Qinling Belt reached a climax with the lack of substantial contractional deformation in Cenozoic sequences heralding the onset of the modern kinematic regime and attainment of high elevation. Observed transitions in the tectonostratigraphy and paleodrainage define different phases of deformation and plateau-wide shifts in stress reorganization, which led to the northward growth and later lateral expansion of the Tibetan Plateau.
The development of planation surfaces requires stable tectonic and climatic conditions. However, it is difficult to discuss in detail how tectonic movement and/or climate change affects erosion, deposition, and uplift associated with the development, formation, and disintegration of planation surface. This article presents a case study on the development and formation of the Tangxian planation surface (TXPS) by establishing the magnetostratigraphy of one piedmont deposition section related to planation, and combining the depositional sequence overlying TXPS and basin sediments. Further, we discuss the role of tectonics and climate change in the geomorphic evolution of the TXPS during the late Cenozoic and revise the final formation age to be ca. 3.1 Ma by the relative deposition process. The vertical rates of the main fault constrained by different geomorphic surfaces and stable deposition in the basin show stable and moderate tectonic activity in the study area since the Pliocene, and a series of sedimentary records reveal that the climate in North China was stably warm-humid from the late Miocene to early Pliocene. Stable tectonic activity and stable climate were important bases for pediment development; however, abrupt climatic changes during the late Pliocene might be the main driving force of the final formation of the TXPS in North China.
Earth and Space Science Open Archive This preprint has been submitted to and is under consideration at Geophysical Research Letters. ESSOAr is a venue for early communication or feedback before peer review. Data may be preliminary.Learn more about preprints preprintOpen AccessYou are viewing the latest version by default [v1]Mud volcanoes influences on the seismicity behaviors indicated from z and b valueAuthorsGegeHuiiDGang ZhiLiChuangSuniDYipengZhangPengchengWangPeizhenZhangSee all authors Gege HuiiDCorresponding Author• Submitting AuthorSun Yat-Sen UniversityiDhttps://orcid.org/0000-0002-4843-4217view email addressThe email was not providedcopy email addressGang Zhi LiSchool of Earth Sciences and Engineering, Sun Yat-sen Universityview email addressThe email was not providedcopy email addressChuang SuniDSchool of Earth Sciences and Engineering, Sun Yat-sen UniversityiDhttps://orcid.org/0000-0002-0716-4548view email addressThe email was not providedcopy email addressYipeng ZhangSchool of Earth Science and Geological EngineeringSun Yat-Sen Universityview email addressThe email was not providedcopy email addressPengcheng WangOcean University of Chinaview email addressThe email was not providedcopy email addressPeizhen ZhangSchool of Earth Sciences and Engineering, Sun Yat-sen Universityview email addressThe email was not providedcopy email address
<p>Supplemental Text S1: Demagnetization and tests. Text S2: Anisotropy of magnetic susceptibility (AMS) analyses. Text S3: Detrital Zircons U-Pb Ages test. Figure S1: Anhua sampling section. Figure S2: Photographs of the sampled Anhua-Huicheng Basin section. Figure S3: Orthogonal (Zijderveld) vector plots of the representative thermal demagnetization behaviors of specimens from the Anhua section. Figure S4: Equal-area plots of accepted ChRMs (185 sites) from the Anhua section in (a) geographic and (b) tilt-corrected coordinates. Figure S5: AMS data. Table S1: Main characteristics and interpretations of major sedimentary facies in this study. Table S2: Fossils were discovered along the West Qinling Belt. Table S3: Zircon U-Pb geochronological analyses. Table S4: Quantitative comparison of age distributions for the Anhua Basin (Z1&Z2; Z3&Z4). </p>
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)