scholarly journals A photogrametric study on active faults in the Nepal Himalayas

1982 ◽  
Vol 2 ◽  
pp. 67-80
Author(s):  
Takashi Nakata
Keyword(s):  
Active Fault ◽  
Late Quaternary ◽  
Lateral Displacement ◽  
Active Faults ◽  
Aerial Photographs ◽  
Fault System ◽  
Lateral Movement ◽  
Active Faulting ◽  
Quaternary Period ◽  
Late Quaternary Period

Active faults in the Nepal Himalayas are identified by means of interpretation of vertical aerial photographs. They are mainly distributed along the major tectonic lines as older geological faults and are classified into four groups, the Main Central Active Fault system, the active faults in the Lower Himalayas, the Main Boundary Active Fault system and active faults along the Himalayan Front Fault. The mode of active faulting is closely related to the strikes of the faults. Along the NW-SE and NE-SW trending faults, lateral displacement with northward drop is prevailing, and right-lateral movement along the former and left-lateral movement along the latter is a rule in the sense of displacements. On the other hand, dip-slip faulting is observed mainly along the E-W trending faults belonging to the Main Boundary Active Fault system. However, apparent displacement along the faults is mostly of northward drop. It is considered that active faulting along the major tectonic lines except the Himalayan Front Fault does not favor the upheaval of the Himalayan ranges during the late Quaternary period.

scholarly journals Morphotectonic Kinematic Indicators along the Vigan-Aggao Fault: The Western Deformation Front of the Philippine Fault Zone in Northern Luzon, the Philippines

Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 83 ◽  
Author(s):  
Rolly E. Rimando ◽  
Jeremy M. Rimando
Keyword(s):  
Fault Zone ◽  
Active Fault ◽  
Active Faults ◽  
Vertical Component ◽  
The Philippines ◽  
Google Earth ◽  
Fault System ◽  
Philippine Sea Plate ◽  
Oblique Convergence ◽  
Philippine Fault Zone

The Vigan-Aggao Fault is a 140-km-long complex active fault system consisting of multiple traces in the westernmost part of the Philippine Fault Zone (PFZ) in northern Luzon, the Philippines. In this paper, its traces, segmentation, and oblique left-lateral strike-slip motion are determined from horizontal and vertical displacements measured from over a thousand piercing points pricked from displaced spurs and streams observed from Google Earth Pro satellite images. This work marks the first instance of the extensive use of Google Earth as a tool in mapping and determining the kinematics of active faults. Complete 3D image coverage of a major thoroughgoing active fault system is freely and easily accessible on the Google Earth Pro platform. It provides a great advantage to researchers collecting morphotectonic displacement data, especially where access to aerial photos covering the entire fault system is next to impossible. This tool has not been applied in the past due to apprehensions on the positional measurement accuracy (mainly of the vertical component). The new method outlined in this paper demonstrates the applicability of this tool in the detailed mapping of active fault traces through a neotectonic analysis of fault-zone features. From the sense of motion of the active faults in northern Luzon and of the major bounding faults in central Luzon, the nature of deformation in these regions can be inferred. An understanding of the kinematics is critical in appreciating the distribution and the preferred mode of accommodation of deformation by faulting in central and northern Luzon resulting from oblique convergence of the Sunda Plate and the Philippine Sea Plate. The location, extent, segmentation patterns, and sense of motion of active faults are critical in coming up with reasonable estimates of the hazards involved and identifying areas prone to these hazards. The magnitude of earthquakes is also partly dependent on the type and nature of fault movement. With a proper evaluation of these parameters, earthquake hazards and their effects in different tectonic settings worldwide can be estimated more accurately.

scholarly journals Topographic Anaglyphs from Detailed Digital Elevation Models Covering Inland and Seafloor for the Tectonic Geomorphology Studies in and around Yoron Island, Ryukyu Arc, Japan

Geosciences ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 363 ◽  
Author(s):  
Hideaki Goto ◽  
Kohsaku Arai ◽  
Taichi Sato
Keyword(s):  
Late Quaternary ◽  
Active Faults ◽  
Aerial Photographs ◽  
Stress Axis ◽  
Tectonic Geomorphology ◽  
Surface Model ◽  
The North ◽  
Digital Elevation ◽  
Ryukyu Arc ◽  
Island Shelf

Anaglyphs produced using a digital elevation model (DEM) are effective to identify the characteristic tectono–geomorphic features. The objective of this study is to reinvestigate the tectonic geomorphology and to present novel tectonic maps of the late Quaternary in and around the Yoron island based on the interpretation of extensive topographical anaglyphs along the map areas that cover the inland and seafloor. Vintage aerial photographs are used to produce the 3-m mesh inland digital surface model (DSM); further, the 0.6-s to 2-s-mesh seafloor DEM is processed using the cloud point data generated through previous surveys. Thus, we identify anticlinal deformation on both the Pleistocene marine terrace and the seafloor to the north of the island. The deformation axis extends in a line and is parallel to the general trend of the island shelf. The Tsujimiya fault cuts the marine terraces, which extend to the Yoron basin’s seafloor. If we assume that the horizontal compressive stress axis is perpendicular to the island shelf, these properties can easily explain the distribution and style of the active faults and deformation. This study presents an effective methodology to understand the island arc tectonics, especially in case of small isolated islands.

scholarly journals Checklist of sand dune vegetation on the tropical southeastern Brazil coast

Check List ◽  
2017 ◽  
Vol 13 (2) ◽  
pp. 2058 ◽  
Author(s):  
Antonio Janilson Castelo ◽  
João Marcelo Alvarenga Braga
Keyword(s):  
Atlantic Forest ◽  
Late Quaternary ◽  
Sand Dunes ◽  
Southeastern Brazil ◽  
Dune Vegetation ◽  
Quaternary Period ◽  
Floristic Survey ◽  
Marine Sand ◽  
Late Quaternary Period ◽  
Janeiro State

Restingas are mosaics of plant communities living on marine sand deposits of the late Quaternary period, located between the sea and the Atlantic Forest. This study presents the diversity of the vegetation of coastal sand dunes in the southeastern coast of Brazil. A floristic survey and bibliographic review of the nine restinga regions of Rio de Janeiro state was carried out, and information is presented about the habit, life form, dispersion syndrome, distribution, and biome occurrence of each species. Ninety-eight species were recorded, distributed among 81 genera and 38 families, of which the most diverse are Asteraceae (12 species), Poaceae (12 species), Fabaceae (11 species), and Rubiaceae (6 species). The majority of species have herbaceous habits and predominantly are camephyte-autochoric species. They present wide geographical distributions or are restricted to just some Brazilian states and are more similar to the Atlantic Forest biome.

Solar system exposure to supernova γ radiation

2020 ◽  
pp. 1-14
Author(s):  
G. Robert Brakenridge
Keyword(s):  
Solar System ◽  
Solar Flares ◽  
Radiation Effects ◽  
Late Quaternary ◽  
Quaternary Period ◽  
Cosmogenic Isotope ◽  
Γ Radiation ◽  
Type Ia ◽  
Late Quaternary Period ◽  
Planetary Habitability

Abstract Planetary habitability may be affected by exposure to γ radiation from supernovae (SNe). Records of Earth history during the late Quaternary Period (40 000 years to present) allow testing for specific SN γ radiation effects. SNe include Type Ia white dwarf explosions, Type Ib, c and II core collapses, and many γ burst objects. Surveys of galactic SNe remnants offer a nearly complete accounting for this time and including SN distances and ages. Terrestrial changes in records of the cosmogenic isotope 14C are here compared to SN-predicted changes. SN γ emission occurs mainly within 3 years; average per-event total emissions of 4 × 1049 erg are used for comparison of close events There are 18 SNe ≤ 1.5 kpc, and brief 14C anomalies are reported for eight of the closest. Four are notable (BP is year before 1950 CE): the older Vela SNR and an abrupt 30‰ del 14C rise at 12 740 BP; S165 and a 20‰ rise at 7431 BP; Vela Jr. and a 14‰ rise at 2765 BP; and HB9 and a 9‰ rise at 5372 BP. Rapid-increase anomalies in 14C production have been attributed to cosmic rays from exceptionally large solar flares. However, the proximity and ages of these SNe, the probable size and duration of their γ emissions, the predicted effects on 14C, and the agreement with 14C records together support SNe causation. Also, the supposed solar-caused 14C anomalies at CE 774 and 993 may instead have been caused by the SNe associated with the G190.9-2.2 and G347.3-00.5 remnants. Both are of appropriate age and distance.

scholarly journals Understanding Abrupt Climate Change in the Late Quaternary

Eos ◽  
2021 ◽  
Vol 102 ◽  
Author(s):  
Raymond Bradley ◽  
Henry Diaz
Keyword(s):  
Climate Change ◽  
Ocean Circulation ◽  
Climate Changes ◽  
Late Quaternary ◽  
Abrupt Climate Change ◽  
Quaternary Period ◽  
Late Quaternary Period ◽  
The Tropics

During the late Quaternary period, a series of abrupt climate changes in the tropics and sub-tropics driven by changes in ocean circulation were both dramatic and disruptive.

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