Trond Ryberg | Helmholtz-Zentrum Potsdam (original) (raw)

Papers by Trond Ryberg

Research paper thumbnail of The crustal Architecture and the seismogenic coupling Zone in southern central Chile (38° S) derived from Reflection Seismic Imaging within Project TIPTEQ

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Research paper thumbnail of The San Gabriel Mountains bright reflective zone: possible evidence of young mid-crustal thrust faulting in southern California

Tectonophysics, 1998

... 0 0') LO " ,, Cl 0,1 CO 09 " (1) qi.deo "o'o ( E... more ... 0 0') LO " ,, Cl 0,1 CO 09 " (1) qi.deo "o'o ( E ou " e (D 0 u (iI III 6 6 ,e, 0"6 8 0... . o 0 1' 2 0 0 D u' ,. 0 CO I ' LO 0 Lt , ""0 , . . . z . . = : o6F c T. Ryberg, GS Fuis ... We thank Bill Lutter for supplying an im proved velocity inversion (over that in Fuis et al., 1996) for processing the CMP data. ...

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Research paper thumbnail of Deep crustal profile across the southern Karoo Basin and Beattie Magnetic Anomaly, South Africa: Integrated interpretation with tectonic implications

Epic3south African Journal of Geology Geological Soc South Africa 114 Pp 265 292 Issn 1012 0750, Dec 1, 2011

© 2011 Geological Society of South Africa. DEEP CRUSTAL PROFILE ACROSS THE SOUTHERN KAROO BASIN A... more © 2011 Geological Society of South Africa. DEEP CRUSTAL PROFILE ACROSS THE SOUTHERN KAROO BASIN AND BEATTIE MAGNETIC ANOMALY, SOUTH AFRICA: AN INTEGRATED INTERPRETATION WITH TECTONIC IMPLICATIONS. ...

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Research paper thumbnail of The "LARSE" Project - Working Toward a Safer Future for Los Angeles

Fact Sheet, 1999

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Research paper thumbnail of Observation of high-frequency teleiseismic Pn on the long-range Quartz profile across northern Eurasia

Journal of Geophysical Research, 1995

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Research paper thumbnail of Structure of the Upper Mantle Beneath Northern Eurasia Derived from Russian Deep-Seismic PNE Profiles

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Research paper thumbnail of Submarine permafrost depth from ambient seismic noise

Geophysical Research Letters, 2015

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Research paper thumbnail of Crustal structure of northwest Namibia: Evidence for plume-rift-continent interaction

Geology, 2015

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Research paper thumbnail of First results of a Pn-tomography study from an active on- and offshore seismic experiment at the Walvis Ridge in northern Namibia

Passive continental margins offer the unique opportunity to study the processes involved in conti... more Passive continental margins offer the unique opportunity to study the processes involved in continental extension and break up. Within the LISPWAL project (part of the SAMPLE SPP), in 2011 combined on- and offshore seismic experiments designed to characterize the Southern African passive margin at the Walvis Ridge in northern Namibia were conducted. In addition to extensive analysis of the crustal structures, the velocity structure of the upper mantle was a subject of this survey. 200 land stations were recording Pn arrivals from five offshore airgun lines. Due to high data quality we were able to identify about 370000 Pn travel times with source-receiver distances between 160 and 470 km used for a Pn-tomography. Various synthetic tests were conducted to evaluate the dependence of the mantle velocity model from the delay times through the crust and to determine the resolving capability. The resulting velocity model for the mantle is showing coast parallel stripes of lower and higher...

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Research paper thumbnail of Deep crustal structure of the Walvis Ridge at the junction with the Namibian coast

The Walvis Ridge perpendicular to the African coast offshore Namibia is believed to be caused by ... more The Walvis Ridge perpendicular to the African coast offshore Namibia is believed to be caused by a long-lived hotspot, which started to erupt with the opening of the South Atlantic in mid Cretaceous. The ridge in combination with the large igneous provinces (Etendeka and Parana) in South America and Namibia is today considered to be a classical model for hotspot driven continental break-up. To unravel details on how the crust and mantle were modified by such a major thermal event, a large-scale geophysical on- and offshore experiment was conducted in 2011. We present p-wave velocity models of two active seismic profiles along and across Walvis Ridge. The profile along the ridge continues onshore, has a total length of ~730 km and consists of 28 ocean bottom stations, 50 land stations and 8 dynamite shots. This section reveals a complex structure with multiple buried seamounts, strong lateral velocity gradients and indication of a high velocity body at the crust-mantle boundary benea...

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Research paper thumbnail of Seismic imaging of the geothermal area in Tarutung (Sumatra, Indonesia): Comparison of local earthquake and ambient noise tomography

A joint German-Indonesian research initiative is conducted to support the geothermal energy devel... more A joint German-Indonesian research initiative is conducted to support the geothermal energy development in Indonesia, where one important aspect is exploration technology. An almost unexplored region located in northern Sumatra (Indonesia) was chosen to develop and demonstrate an integrated exploration strategy which includes structural geology, active seismics, passive seismology, and magnetotelluric investigations. The geothermal potential at this site is mainly determined by the Sumatran fault system and its interplay with young volcanism associated with subduction zone processes. Within the passive seismology study, a temporary network of 42 stations was installed around the city of Tarutung running over a period of 10 month from May 2011 until February 2012. The Sumatran fault was covered at the center of the network, and stations were distributed within a radius of 20 km with spacings of about 5 km on average. The collected data allow for the 3D imaging of seismic velocities a...

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Research paper thumbnail of Geophysical Studies of the Lithosphere Along the Dead Sea Transform

Modern Approaches in Solid Earth Sciences, 2014

ABSTRACT In this chapter we report on the deep structure of the Dead Sea Transform (DST) as deriv... more ABSTRACT In this chapter we report on the deep structure of the Dead Sea Transform (DST) as derived from geophysical observations and numerical modelling, calibrated by geological and geodynamic evidence. We use seismics, seismology and gravity to study the crust and lithosphere of the Dead Sea Transform (DST) system. These observations are integrated with 3D thermo-mechanical modelling of the evolution of the DST through time to understand the deeper structure of the DST. The three seismic profiles crossing the DST from the Mediterranean in the West to the Jordan highlands in the East show an increase in Moho depth from about 25 km to about 35 km; with only minor topography. This depth increase of about 10 km of the Moho from West to East is also found in tomographic images using regional and teleseismic events, which shows additionally a N – S trending thickening of the crust under the Arava/Araba Fault (AF). In the Dead Sea Basin (DSB) proper the imaging of the Moho is complicated by the presence of the Lisan Salt dome. From these results and other evidence we conclude that the Dead Sea basin is a mostly upper crustal feature with a decoupling zone at about 20 km depth. Using SKS waves we find below the Moho under the DST a narrow, ca. 20 km wide, vertical decoupling zone reaching into the mantle, representing the boundary layer between the African and Arabian plates. This observation agrees with the results from the study of surface waves that also show a region of reduced S-velocities under the DST, reaching down into the lithosphere. Whereas the lithosphere thins gradually east of the DST from N to S from ca. 80 to ca. 67 km, below about 120 km depth little structure can be observed in tomographic images. The abovementioned observational constraints can all be fitted with the classical pull-apart model, if the lithosphere was thermally eroded to 80 km thickness about 20 Ma ago, combined with weak rheologies for crust and upper mantle. The most likely explanation of the features described is thus a thinning of the lithosphere around the DST in the Late Cenozoic, likely following by rifting and spreading of the Red Sea.

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Research paper thumbnail of Seismogram offers insight into Oklahoma City bombing

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Research paper thumbnail of Results of geophysical studies across the Dead Sea Transform: The Arava/Araba Valley and the Dead Sea Basin

The Dead Sea Transform (DST) in the Middle East is a fault zone of about 1000 km length, with a t... more The Dead Sea Transform (DST) in the Middle East is a fault zone of about 1000 km length, with a total of ca. 107 km of left-lateral transform motion since early Miocene (~ 20 My). It shows uplifted flanks and several deep pull-apart basins, most prominently the Dead Sea ...

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Research paper thumbnail of Images of crust beneath southern California will aid study of earthquakes and their effects

... Gary S. Fuis, David A. Okaya, Robert W. Clayton, William J. Lutter, Trond Ryberg, Thomas M. B... more ... Gary S. Fuis, David A. Okaya, Robert W. Clayton, William J. Lutter, Trond Ryberg, Thomas M. Brocher, Thomas M. Henyey, Mark L. Benthien, Paul M. Davis, James Mori, Rufiis D. Catchings, Uri S. ten Brink, Monica D. Kohler, Kim D. Klitgord, and Robert G. Bohannon ...

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Research paper thumbnail of Heterogeneity of the Uppermost Mantle Inferred From Controlled-Source Seismology

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Research paper thumbnail of Finite-Difference Simulations of Seismic Wavefields in Isotropic and Anisotropic Earth Models

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Research paper thumbnail of Finite Difference Modelling of Seismic Wave Phenomena within the Earth’s Upper Mantle

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Research paper thumbnail of Finite difference modelling of elastic wave propagation in the Earth’s uppermost mantle

ABSTRACT

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Research paper thumbnail of Shallow architecture of the Wadi Araba fault (Dead Sea Transform) from high-resolution seismic investigations

In a high-resolution small scale seismic experiment we investigated the shallow structure of the ... more In a high-resolution small scale seismic experiment we investigated the shallow structure of the Wadi Araba Fault (WAF), the principal fault strand of the Dead Sea Transform System between the Gulf of Aqaba/Eilat and the Dead Sea. The experiment consisted of 8 sub-parallel 1 km long seismic lines crossing the WAF. The recording station spacing was 5 meters and the source point distance was 20 m. The first break tomography yields insight into the fault structure down to a depth of about 200 m. The velocity structure varies from one section to the other which were 1 to 2 km apart, but distinct velocity variations along the fault are visible between several profiles. The reflection seismic images show positive flower structures and indications for different sedimentary layers at the two sides of the main fault. Often the superficial sedimentary layers are bent upward close to the WAF. Our results indicate that this section of the fault (at shallow depths) is characterized by a transpressional regime. We detected a 100 to 300 m wide heterogeneous zone of deformed and displaced material which, however, is not characterized by low seismic velocities at a larger scale. At greater depth the geophysical images indicate a blocked cross-fault structure. The structure revealed, fault cores not wider than 10 m, are consistent with scaling from wear mechanics and with the low loading to healing ratio anticipated for the fault.

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Research paper thumbnail of The crustal Architecture and the seismogenic coupling Zone in southern central Chile (38° S) derived from Reflection Seismic Imaging within Project TIPTEQ

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The San Gabriel Mountains bright reflective zone: possible evidence of young mid-crustal thrust faulting in southern California

Tectonophysics, 1998

... 0 0') LO " ,, Cl 0,1 CO 09 " (1) qi.deo "o'o ( E... more ... 0 0') LO " ,, Cl 0,1 CO 09 " (1) qi.deo "o'o ( E ou " e (D 0 u (iI III 6 6 ,e, 0"6 8 0... . o 0 1' 2 0 0 D u' ,. 0 CO I ' LO 0 Lt , ""0 , . . . z . . = : o6F c T. Ryberg, GS Fuis ... We thank Bill Lutter for supplying an im proved velocity inversion (over that in Fuis et al., 1996) for processing the CMP data. ...

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Research paper thumbnail of Deep crustal profile across the southern Karoo Basin and Beattie Magnetic Anomaly, South Africa: Integrated interpretation with tectonic implications

Epic3south African Journal of Geology Geological Soc South Africa 114 Pp 265 292 Issn 1012 0750, Dec 1, 2011

© 2011 Geological Society of South Africa. DEEP CRUSTAL PROFILE ACROSS THE SOUTHERN KAROO BASIN A... more © 2011 Geological Society of South Africa. DEEP CRUSTAL PROFILE ACROSS THE SOUTHERN KAROO BASIN AND BEATTIE MAGNETIC ANOMALY, SOUTH AFRICA: AN INTEGRATED INTERPRETATION WITH TECTONIC IMPLICATIONS. ...

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Research paper thumbnail of The "LARSE" Project - Working Toward a Safer Future for Los Angeles

Fact Sheet, 1999

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Research paper thumbnail of Observation of high-frequency teleiseismic Pn on the long-range Quartz profile across northern Eurasia

Journal of Geophysical Research, 1995

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Research paper thumbnail of Structure of the Upper Mantle Beneath Northern Eurasia Derived from Russian Deep-Seismic PNE Profiles

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Submarine permafrost depth from ambient seismic noise

Geophysical Research Letters, 2015

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Research paper thumbnail of Crustal structure of northwest Namibia: Evidence for plume-rift-continent interaction

Geology, 2015

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Research paper thumbnail of First results of a Pn-tomography study from an active on- and offshore seismic experiment at the Walvis Ridge in northern Namibia

Passive continental margins offer the unique opportunity to study the processes involved in conti... more Passive continental margins offer the unique opportunity to study the processes involved in continental extension and break up. Within the LISPWAL project (part of the SAMPLE SPP), in 2011 combined on- and offshore seismic experiments designed to characterize the Southern African passive margin at the Walvis Ridge in northern Namibia were conducted. In addition to extensive analysis of the crustal structures, the velocity structure of the upper mantle was a subject of this survey. 200 land stations were recording Pn arrivals from five offshore airgun lines. Due to high data quality we were able to identify about 370000 Pn travel times with source-receiver distances between 160 and 470 km used for a Pn-tomography. Various synthetic tests were conducted to evaluate the dependence of the mantle velocity model from the delay times through the crust and to determine the resolving capability. The resulting velocity model for the mantle is showing coast parallel stripes of lower and higher...

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Research paper thumbnail of Deep crustal structure of the Walvis Ridge at the junction with the Namibian coast

The Walvis Ridge perpendicular to the African coast offshore Namibia is believed to be caused by ... more The Walvis Ridge perpendicular to the African coast offshore Namibia is believed to be caused by a long-lived hotspot, which started to erupt with the opening of the South Atlantic in mid Cretaceous. The ridge in combination with the large igneous provinces (Etendeka and Parana) in South America and Namibia is today considered to be a classical model for hotspot driven continental break-up. To unravel details on how the crust and mantle were modified by such a major thermal event, a large-scale geophysical on- and offshore experiment was conducted in 2011. We present p-wave velocity models of two active seismic profiles along and across Walvis Ridge. The profile along the ridge continues onshore, has a total length of ~730 km and consists of 28 ocean bottom stations, 50 land stations and 8 dynamite shots. This section reveals a complex structure with multiple buried seamounts, strong lateral velocity gradients and indication of a high velocity body at the crust-mantle boundary benea...

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Research paper thumbnail of Seismic imaging of the geothermal area in Tarutung (Sumatra, Indonesia): Comparison of local earthquake and ambient noise tomography

A joint German-Indonesian research initiative is conducted to support the geothermal energy devel... more A joint German-Indonesian research initiative is conducted to support the geothermal energy development in Indonesia, where one important aspect is exploration technology. An almost unexplored region located in northern Sumatra (Indonesia) was chosen to develop and demonstrate an integrated exploration strategy which includes structural geology, active seismics, passive seismology, and magnetotelluric investigations. The geothermal potential at this site is mainly determined by the Sumatran fault system and its interplay with young volcanism associated with subduction zone processes. Within the passive seismology study, a temporary network of 42 stations was installed around the city of Tarutung running over a period of 10 month from May 2011 until February 2012. The Sumatran fault was covered at the center of the network, and stations were distributed within a radius of 20 km with spacings of about 5 km on average. The collected data allow for the 3D imaging of seismic velocities a...

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Research paper thumbnail of Geophysical Studies of the Lithosphere Along the Dead Sea Transform

Modern Approaches in Solid Earth Sciences, 2014

ABSTRACT In this chapter we report on the deep structure of the Dead Sea Transform (DST) as deriv... more ABSTRACT In this chapter we report on the deep structure of the Dead Sea Transform (DST) as derived from geophysical observations and numerical modelling, calibrated by geological and geodynamic evidence. We use seismics, seismology and gravity to study the crust and lithosphere of the Dead Sea Transform (DST) system. These observations are integrated with 3D thermo-mechanical modelling of the evolution of the DST through time to understand the deeper structure of the DST. The three seismic profiles crossing the DST from the Mediterranean in the West to the Jordan highlands in the East show an increase in Moho depth from about 25 km to about 35 km; with only minor topography. This depth increase of about 10 km of the Moho from West to East is also found in tomographic images using regional and teleseismic events, which shows additionally a N – S trending thickening of the crust under the Arava/Araba Fault (AF). In the Dead Sea Basin (DSB) proper the imaging of the Moho is complicated by the presence of the Lisan Salt dome. From these results and other evidence we conclude that the Dead Sea basin is a mostly upper crustal feature with a decoupling zone at about 20 km depth. Using SKS waves we find below the Moho under the DST a narrow, ca. 20 km wide, vertical decoupling zone reaching into the mantle, representing the boundary layer between the African and Arabian plates. This observation agrees with the results from the study of surface waves that also show a region of reduced S-velocities under the DST, reaching down into the lithosphere. Whereas the lithosphere thins gradually east of the DST from N to S from ca. 80 to ca. 67 km, below about 120 km depth little structure can be observed in tomographic images. The abovementioned observational constraints can all be fitted with the classical pull-apart model, if the lithosphere was thermally eroded to 80 km thickness about 20 Ma ago, combined with weak rheologies for crust and upper mantle. The most likely explanation of the features described is thus a thinning of the lithosphere around the DST in the Late Cenozoic, likely following by rifting and spreading of the Red Sea.

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Research paper thumbnail of Seismogram offers insight into Oklahoma City bombing

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Research paper thumbnail of Results of geophysical studies across the Dead Sea Transform: The Arava/Araba Valley and the Dead Sea Basin

The Dead Sea Transform (DST) in the Middle East is a fault zone of about 1000 km length, with a t... more The Dead Sea Transform (DST) in the Middle East is a fault zone of about 1000 km length, with a total of ca. 107 km of left-lateral transform motion since early Miocene (~ 20 My). It shows uplifted flanks and several deep pull-apart basins, most prominently the Dead Sea ...

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Research paper thumbnail of Images of crust beneath southern California will aid study of earthquakes and their effects

... Gary S. Fuis, David A. Okaya, Robert W. Clayton, William J. Lutter, Trond Ryberg, Thomas M. B... more ... Gary S. Fuis, David A. Okaya, Robert W. Clayton, William J. Lutter, Trond Ryberg, Thomas M. Brocher, Thomas M. Henyey, Mark L. Benthien, Paul M. Davis, James Mori, Rufiis D. Catchings, Uri S. ten Brink, Monica D. Kohler, Kim D. Klitgord, and Robert G. Bohannon ...

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Research paper thumbnail of Heterogeneity of the Uppermost Mantle Inferred From Controlled-Source Seismology

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Finite-Difference Simulations of Seismic Wavefields in Isotropic and Anisotropic Earth Models

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Finite Difference Modelling of Seismic Wave Phenomena within the Earth’s Upper Mantle

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Finite difference modelling of elastic wave propagation in the Earth’s uppermost mantle

ABSTRACT

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Research paper thumbnail of Shallow architecture of the Wadi Araba fault (Dead Sea Transform) from high-resolution seismic investigations

In a high-resolution small scale seismic experiment we investigated the shallow structure of the ... more In a high-resolution small scale seismic experiment we investigated the shallow structure of the Wadi Araba Fault (WAF), the principal fault strand of the Dead Sea Transform System between the Gulf of Aqaba/Eilat and the Dead Sea. The experiment consisted of 8 sub-parallel 1 km long seismic lines crossing the WAF. The recording station spacing was 5 meters and the source point distance was 20 m. The first break tomography yields insight into the fault structure down to a depth of about 200 m. The velocity structure varies from one section to the other which were 1 to 2 km apart, but distinct velocity variations along the fault are visible between several profiles. The reflection seismic images show positive flower structures and indications for different sedimentary layers at the two sides of the main fault. Often the superficial sedimentary layers are bent upward close to the WAF. Our results indicate that this section of the fault (at shallow depths) is characterized by a transpressional regime. We detected a 100 to 300 m wide heterogeneous zone of deformed and displaced material which, however, is not characterized by low seismic velocities at a larger scale. At greater depth the geophysical images indicate a blocked cross-fault structure. The structure revealed, fault cores not wider than 10 m, are consistent with scaling from wear mechanics and with the low loading to healing ratio anticipated for the fault.

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