The crust structure of the North-South earthquake belt in China revealed from integrated analyses of the deep seismic soundings and gravity data

2017 ◽  
Author(s):  
Yang Zhao* ◽  
Lianghui Guo ◽  
Lei Shi
Keyword(s):  
Gravity Data ◽  
Crust Structure ◽  
The North ◽  
Deep Seismic Soundings

scholarly journals 2D density model of the Chinese continental lithosphere along a NW-SE transect

2015 ◽  
Vol 45 (2) ◽  
pp. 135-148
Author(s):  
Barbora Šimonová ◽  
Miroslav Bielik ◽  
Jana Dérerová
Keyword(s):  
Seismic Velocity ◽  
Qaidam Basin ◽  
Gravity Data ◽  
Junggar Basin ◽  
Density Model ◽  
Low Velocity ◽  
The North ◽  
Deep Seismic Soundings ◽  
Qilian Orogen ◽  
North Western

Abstract This paper presents a 2D density model along a transect from NW to SE China. The model was first constructed by the transformation of seismic velocity to density, revealed by previous deep seismic soundings (DSS) investigations in China. Then, the 2D density model was updated using the GM-SYS software by fitting the computed to the observed gravity data. Based on the density distribution of anomalous layers we divided the Chinese continental crust along the transect into three regions: north-western, central and south-eastern. The first one includes the Junggar Basin, Tianshan and Tarim Basin. The second part consists of the Qilian Orogen, the Qaidam Basin and the Songpan Ganzi Basin. The third region is represented by the Yangtze and the Cathaysia blocks. The low velocity body (vp =5.2 – 6.2 km/s) at the junction of the North-western and Central parts at a depth between 21 – 31 km, which was discovered out by DSS, was also confirmed by our 2D density modelling.

scholarly journals Increased Water Storage in the Qaidam Basin, the North Tibet Plateau from GRACE Gravity Data

PLoS ONE ◽  
2015 ◽  
Vol 10 (10) ◽  
pp. e0141442 ◽  
Author(s):  
Jiu Jimmy Jiao ◽  
Xiaotao Zhang ◽  
Yi Liu ◽  
Xingxing Kuang
Keyword(s):  
Qaidam Basin ◽  
Gravity Data ◽  
Water Storage ◽  
Tibet Plateau ◽  
The North

scholarly journals Monitoring mass changes in the Volta River basin using GRACE satellite gravity and TRMM precipitation

2012 ◽  
Vol 18 (4) ◽  
pp. 549-563 ◽  
Author(s):  
Vagner G. Ferreira ◽  
Zheng Gong ◽  
Samuel A. Andam-Akorful
Keyword(s):  
River Basin ◽  
Gravity Data ◽  
West African ◽  
Rainfall Time Series ◽  
Tropical Rainfall Measurement Mission ◽  
Satellite Gravity ◽  
Rainfall Events ◽  
The North ◽  
Trmm Precipitation ◽  
Grace Satellite

GRACE satellite gravity data was used to estimate mass changes within the Volta River basin in West African for the period of January, 2005 to December, 2010. We also used the precipitation data from the Tropical Rainfall Measurement Mission (TRMM) to determine relative contributions source to the seasonal hydrological balance within the Volta River basin. We found out that the seasonal mass change tends to be detected by GRACE for periods from 1 month in the south to 4 months in the north of the basin after the rainfall events. The results suggested a significant gain in water storage in the basin at reference epoch 2007.5 and a dominant annual cycle for the period under consideration for both in the mass changes and rainfall time series. However, there was a low correlation between mass changes and rainfall implying that there must be other processes which cause mass changes without rainfall in the upstream of the Volta River basin.

scholarly journals Current knowledge on the crustal properties of Italy

1994 ◽  
Vol 37 (5 Sup.) ◽  
Author(s):  
C. Morelli
Keyword(s):  
Adriatic Sea ◽  
Current Knowledge ◽  
Gravity Data ◽  
Maximum Depth ◽  
Gravity Models ◽  
Tyrrhenian Sea ◽  
Po Plain ◽  
Reflection Seismic ◽  
Adriatic Plate ◽  
The North

The recent advances in experimental petrography together with the information derived from the super-deep drilling projects have provided additional constraints for the interpretation of refraction and reflection seismic data. These constraints can also be used in the interpretation of magnetic and gravity data to resolve nonuniqueness. In this study, we re-interpret the magnetic and gravity data of the Italian peninsula and neighbouring areas. In view of the constraints mentioned above, it is now possible to find an agreement between the seismic and gravity models of the Central Alps. By taking into account the overall crustal thickness, we have recognized the existence of three types of Moho: 1) European which extends to the north and west of the peninsula and in the Corsican-Sardinian block. Its margin was the foreland in the Alpine Orogeny and it was the ramp on which European and Adriatic mantle and crustal slices were overthrusted. This additional load caused bending and deepening and the Moho which now lies beneath the Adriatic plate reaching a maximum depth of approximately 75 km. 2) Adriatic (or African) which lies beneath the Po plain, the Apennines and the Adriatic Sea. The average depth of the Moho is about 30-35 km below the Po plain and the Adriatic Sea and it increases toward the Alps and the Tyrrhenian Sea (acting as foreland along this margin). The maximum depth (50 km) is reached in Calabria. 3) Pery-Tyrrhenian. This is an oceanic or thinned continental crust type of Moho. It borders the oceanic Moho of the Tyrrhenian Sea and it acquires a transitional character in the Ligurian and Provençal basins (<15 km thickness) while further thickening occurs toward the East where the Adriatic plate is overthrusted. In addition, the interpretation of the heat flow data appears to confirm the origin of this Moho and its geodynamic allocation.

scholarly journals Shallow crust structure of the Büyük Menderes graben through an analysis of gravity data

2018 ◽  
Vol 27 (6) ◽  
pp. 421-431 ◽  
Author(s):  
F. Figen ALTINOĞLU ◽  
Murat SARI ◽  
Ali AYDIN
Keyword(s):  
Gravity Data ◽  
Crust Structure ◽  
Shallow Crust

The experimental geoid 2020 – the first joint geoid model for the North American and Pacific Geopotential Datum 

2021 ◽  
Author(s):  
Yan Ming Wang ◽  
Xiaopeng Li ◽  
Kevin Ahlgren ◽  
Jordan Krcmaric ◽  
Ryan Hardy ◽  
...  
Keyword(s):  
North American ◽  
Gravity Data ◽  
The United States ◽  
Geodetic Survey ◽  
Airborne Gravity ◽  
Data Sets ◽  
National Geodetic Survey ◽  
Geoid Model ◽  
Satellite Gravity ◽  
The North

&lt;p&gt;For the upcoming North American-Pacific Geopotential Datum of 2022, the National Geodetic Survey (NGS), the Canadian Geodetic Survey (CGS) and the&amp;#160;National Institute of Statistics and Geography of Mexico (INEGI) computed the first joint experimental gravimetric geoid model (xGEOID) on 1&amp;#8217;x1&amp;#8217; grids that covers a region bordered by latitude 0 to 85 degree, longitude 180 to 350 degree east.&amp;#160;xGEOID20 models are computed using terrestrial gravity data, the latest satellite gravity model GOCO06S, altimetric gravity data DTU15, and an additional nine airborne gravity blocks of the GRAV-D project, for a total of 63 blocks. In addition, a digital elevation model in a 3&amp;#8221; grid was produced by combining MERIT, TanDEM-X, and USGS-NED and used for the topographic/gravimetric reductions. The geoid models computed from the height anomalies (NGS) and from the Helmert-Stokes scheme (CGS) were combined using two different weighting schemes, then evaluated against the independent GPS/leveling data sets. The models perform in a very similar way, and the geoid comparisons with the most accurate Geoid Slope Validation Surveys (GSVS) from 2011, 2014 and 2017 indicate that the&amp;#160;relative geoid accuracy&amp;#160;could be around 1-2 cm baseline lengths up to 300 km for these GSVS lines in the United States. The xGEOID20 A/B models were selected from the combined models based on the validation results. The geoid accuracies were also estimated using the forward modeling.&lt;/p&gt;

scholarly journals Combined approach for the unification of levelling networks in New Zealand

2011 ◽  
Vol 1 (4) ◽  
pp. 324-332 ◽  
Author(s):  
Robert Tenzer ◽  
Viliam Vatrt ◽  
Luzi Gan ◽  
Ahmed Abdalla ◽  
Nadim Dayoub
Keyword(s):  
New Zealand ◽  
Gravity Data ◽  
Gravity Anomalies ◽  
Combined Approach ◽  
Network Adjustment ◽  
The North ◽  
Geoidal Geopotential ◽  
Normal Heights ◽  
Orthometric Heights ◽  
Local Vertical Datum

Combined approach for the unification of levelling networks in New ZealandThe unification of levelling networks in New Zealand is done using a combined approach. It utilises the joint levelling network adjustment and the geopotential-value approach. The levelling and normal gravity data are used for a joint adjustment of the levelling networks at the South and North Islands of New Zealand while fixing the heights of tide gauges in Dunedin and Wellington. The results reveal a good quality of levelling data; the STD of residuals is 2 mm for the whole country. The comparison of the newly determined and original normal-orthometric heights confirms the presence of large local vertical datum offsets and systematic levelling errors. Since the geopotential-value approach is based on the Molodensky's theory, the newly adjusted normal-orthometric heights are converted to the normal heights. This conversion is based on applying the cumulative normal to normal-orthometric height correction computed from levelling and gravity anomaly data. In the absence of the observed gravity data the gravity anomalies along levelling lines are generated fromEGM2008. The GPS-levelling data and EGM2008 are used to estimate the average offsets of the jointly adjusted levelling networks at the North and South Islands with respect to World Height System defined by the adopted geoidal geopotential value of W0 = 62636856 ± 0.5 m2s-2; the estimated offsets are 10.6 cm and 27.5 cm.

scholarly journals Oligocene-Miocene extension led to mantle exhumation in the central Ligurian Basin, Western Alpine Domain

2019 ◽  
Author(s):  
Anke Dannowski ◽  
Heidrun Kopp ◽  
Ingo Grevemeyer ◽  
Dietrich Lange ◽  
Martin Thowart ◽  
...  
Keyword(s):  
Gravity Data ◽  
Sedimentary Cover ◽  
Seafloor Spreading ◽  
Wide Angle ◽  
The South ◽  
Seismic Line ◽  
Acoustic Basement ◽  
North West ◽  
The North ◽  
Ligurian Basin

Abstract. The Ligurian Basin is located in the Mediterranean Sea to the north-west of Corsica at the transition from the western Alpine orogen to the Apennine system and was generated by the south-eastward trench retreat of the Apennines-Calabrian subduction zone. Late Oligocene to Miocene rifting caused continental extension and subsidence, leading to the opening of the basin. Yet, it still remains enigmatic if rifting caused continental break-up and seafloor spreading. To reveal its lithospheric architecture, we acquired a state of the art seismic refraction and wide-angle reflection profile in the Ligurian Basin. The seismic line was recorded in the framework of SPP2017 4D-MB, the German component of the European AlpArray initiative, and trends in a NE-SW direction at the centre of the Ligurian Basin, roughly parallel to the French coastline. The seismic data recorded on the newly developed GEOLOG recorder, designed at GEOMAR, are dominated by sedimentary refractions and show mantle Pn arrivals at offsets of up to 70 km and a very prominent wide-angle Moho reflection. The main features share several characteristics (i.e. offset range, continuity) generally associated with continental settings rather than documenting oceanic crust emplaced by seafloor spreading. Seismic tomography results are augmented by gravity data and yield a 7.5–8 km thick sedimentary cover which is directly underlain by serpentinised mantle material at the south-western end of the profile. The acoustic basement at the north-eastern termination is interpreted to be continental crust, thickening towards the NE. Our study reveals that the oceanic domain does not extend as far north as previously assumed and that extension led to extreme continental thinning and exhumation of sub-continental mantle which eventually became serpentinised.

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