Surveys of emergent terraces and U-series ages for ten sites along the coast of East Timor provide estimates of late Quaternary differential vertical strain in the most mature region of the Banda Arc-continent collision complex. Over a distance of ~180 km vertical displacement rates vary between 0.0 and 1.6 meters per 1000 years for the last 150,000 years. Two models of terrace formation (constructional and erosional) are applied to interpret terrace ages from coral ages and to estimate uplift rates. The highest uplift rates are from three sites over a distance of 15 km along the coast. Uplift rates were estimated from corals approximately 20 m above mean sea-level that yield ages of c. 54–74 ka, which correspond to the 3a (c. 49-52 ka) sea-level highstand and a possible highstand or standstill in regression between the 5a sea-level highstand and the 4 sea-level lowstand . These ten sites and resulting variable uplift rates are used constrain a wavelength of deformation due to the fact that recognizable terraces along the coast are not consistent. Terraces cannot be correlated over distances greater than 10 km, vary between 2 to 25 in number, and reach varying altitudes between ~100 and 600 meters above sea-level. The results propose that along an east-west transect a background surface uplift rate increases from 0.1 meter per 1000 years near Subau to 0.5–0.6 meters per 1000 years west of Baucau and remains at that rate for over 170 km. This would indicate a broad wavelength of deformation, possibly related to lithospheric scaled processes. However, superimposed on this background uplift rate is a shorter wavelength (< 15 km) of uplift with a mean of 1.2 meters per 1000 years and peak surface uplift at 1.6 meters per 1000 years. Another interpretation proposes the possibility of at least three shorter wavelength features. The shorter wavelength is likely associated to deformation in the upper crust. This study associates the crustal deformation to Quaternary movement along retro-wedge thrust faults at depth, which indicates active crustal shortening in Timor region.

In 1852, a five-minute long earthquake hit the Banda Arc region that was felt over most of Indonesia. It caused uplift of new islands and sent a tsunami across the Banda Sea that reached a height of 8 meters at Banda Neira and was also registered at Ambon, Saparua and other islands. Records of the 1852 earthquake at multiple locations provide the constraints needed to reconstruct the disastrous event through earthquake intensity analysis and numerical modeling of the tsunami. Using tsunami heights and arrival times as the major constraints, best fit numerical models of the tsunami were constructed using Clawpack. These models indicate that the earthquake was most likely a mega-thrust event along the Tanimbar Trough with a Mw of around 8.4. At least 10-15 meters of elastic strain energy has accumulated along the Tanimbar Through since the 1852 event, and the population in the region has increased exponentially. When another event occurs ≥ that in 1852, there will be many more people and treasure in harms way.

Petrographic and age analysis of sandstones, detailed structural analysis and gravity modeling were conducted to investigate the origin of the Gondwana Sequence in the Timor Region, and to better constrain the tectonic evolution of the active Banda Arc. Our field studies and U/Pb zircon age analysis helped assign most units to either Asian or Australian affinity. Detrital zircon from uplifted Banda forearc units (Asian affinity) have U/Pb ages as young as 80 Ma (Standley and Harris, in press). In contrast, analysis of detrital zircon from Gondwana Sequence sandstones accreted to the Banda Arc from Savu to East Timor are no younger than 234.6 ± 4.0 Ma, and have peak ages at 301 Ma and 1873 Ma with some Archean ages. These age constraints provide a reliable new application for distinguishing rocks units as Asian or Australian affinity. Petrographic and provenance analysis of Triassic Australian affinity greywacke units yield QFL abundances consistent with a proximal, syn-rift, intracratonic or recycled orogen source, from the northeast. The Mount Isa region to the east has the most similar peak U/Pb zircon ages to the Gondwana Sequence. However an extension of this terrane to the west, which would have rifted away during Jurassic breakup, is required to account for the immaturity of the sandstones. Structural measurements of Gondwana Sequence units accreted to the Banda Arc show a northwest - southeast paleo and current maximum stress direction, and vergence mostly to the southeast. Individual thrust sheets are 3 km thick and account for 50% total shortening. The deformational grain of Timor is a hybrid of the east-west strike of Banda Arc and northeast-southwest strike of incoming Australian continental margin structures. The Banda forearc, which is 200 km wide north of Savu, progressively narrows towards East Timor. In order to constrain the location of the forearc, three area-balanced structural models were tested against the gravity field of the Banda Arc. The best fit model requires internal shortening and under-stacking of the forearc beneath the arc, which may account for the cessation of volcanism and uplifted coral terraces north of East Timor.

Coral terrace surveys and U-series ages of coral and mollusk shells yield a surface uplift rate of ~0.6 m/ka for Kisar Island. The small island is located NE of Timor in the active Banda Arc of Indonesia. Based on this rate, Kisar first emerged from the ocean as recently as ~450 ka. Terrace surveys show warping that follows a pattern of east-west striking folds, which are along strike of thrust-related folds of similar wavelength imaged by a seismic reflection profile just offshore. This deformation shows that the emergence of Kisar can be attributed to forearc closure along the south-dipping Kisar Thrust. Terrace morphology and coral ages are best explained by recognizing major terraces as mostly growth terraces and minor terraces as mostly erosional into older growth terraces. All reliable and referable coral U-series ages are marine isotope stage (MIS) 5e (118-128 ka), which encrusted the coast up to 60 m elevation. All coral samples are found below 6 m elevation, but a tridacna (giant clam) shell in growth position at 95 m elevation yields an age of 195 +/- 31 ka, which corresponds to MIS Stage 7. Loose deposits of coral fragments found on top of low terraces between 8 and 20 m elevation yield ages of < 100 years and may represent paleotsunami deposits from previously undocumented seismic activity in the region. The metamorphic rocks of Kisar, Indonesia, which correlate with the Aileu Metamorphic Complex of East Timor, record the breakup of a supercontinent with associated rifting, metamorphism from arc-continent collision, and the growth and exhumation of a new orogenic belt. The protoliths of these rocks are mostly psammitic with minor basaltic and felsic igneous rocks. Geochemical analyses of mafic meta-igneous rocks show rift affinities that are likely related to rifting of Gondwana and later breakup in the Jurassic Period. The Aileu Complex is overlain by younger sedimentary rocks deposited on the northern passive margin of Australia, which collided with the Banda Arc in latest Miocene time. This collision caused metamorphism of the distal edge of the continental margin rocks at conditions of 600-700°C at 6-8 kbar and up to 700-850°C at 8-9 kbar locally, corresponding to depths from 25 to 30 km. These rocks were then rapidly uplifted and exhumed. U-Pb analysis of detrital zircons indicates a Permian to Late Jurassic age of the sedimentary sources and confirm an Australian provenance. The timing of metamorphism of the Aileu Complex is poorly constrained by previous studies, of which only a white mica cooling age of 5.36 +/- 0.05 Ma proved reliable. Prior apatite fission track studies show that all tracks are partially to completely annealed suggesting recent rapid cooling. A domal geometry of the island above the sea floor is expressed in the pinnacle shape. Foliations on Kisar Island generally strike parallel to the coastline, which is may be suggestive of doming. The Kisar Thrust, which is imaged in offshore seismic reflection data, may indicate that the doming corresponds to diapirism into the hinge of an active thrust-related anticline or diapirism of buoyant continental material along the thrust itself.

Campaign GPS measurements during 2001-2003 in the transition between subduction and collision of the Banda arc reveal how strain is partitioned away from the trench and distributed to other parts of the arc-trench system. Genrich, et. al. (1996) conducted a GPS campaign (1992-1994) throughout the Eastern Sunda and Banda arcs that demonstrated partial accretion of the arc to the Australian plate. We reoccupied many of the sites from this earlier study and 7 additional stations, 3 of which are new benchmarks. Our study shortened many baselines and extended the observation epoch to ten years for many key stations. The resulting GPS velocity field for the active Banda arc-continent collision reveals: 1) several mostly rigid crustal blocks exist in the transition from subduction to collision, 2) relative to an Asian reference frame, most of these blocks move in the same direction as the Australian lower plate, but at different rates, 3) block boundaries may exist between the islands of Lombok and Komodo, Flores and Sumba, Savu and West Timor, and between Timor and Darwin, 4) the Timor Trough may account for at least 20 mm/yr of motion between Timor and Darwin, 5) a major transverse fault off the coast of West Timor separates the Savu/Flores/Sumba block from the Timor/Wetar Block and may account for variations in movement in Rote, 6) the Flores thrust moves the eastern Sunda arc north relative to Asia by decreasing amounts to the west, 7) the back-arc Wetar Thrust system takes up the majority of plate convergence between Australia and Asia, and 8) fault boundaries are not found between many blocks, such as various islands of the Sunda arc and forearc with different amounts of motion.

Analysis of foraminifera for synorogenic pelagic units of Rote and Savu Islands, Indonesia, reveals high rates of surface uplift in the past 1.5 Ma of the incipient Banda arc-continent collision. Paleodepth estimates are derived from benthonic forams and ages from planktonic forams. But estimates are complicated, however, by abundant reworking; yet several distinctive species have been found. Synorogenic deposits in western Rote yield forams of biozone Neogene (N) 18 and depths from 5000-5700 meters at the base of the section, and 3600 meters at the top of the section. Eastern Rote yields forams of N 19/20 - N 22 and depths from 5400-5700 meters. Central Rote yields N 21 and depths from 5000-5700 meters. Because all of the sections are presently about the same elevation (~200 m), long-term surface uplift rates are slightly higher (1.84-3.29 m/yr) in eastern and central Rote than those in western Rote. Forams from Savu yield ages of N19/20 - N 22. Across Savu depth estimates range from 3200-5700 meters, which yields a range of uplift rates from 1.86 mm/yr in SE Savu to 3.25 mm/yr in Central Savu. These results indicate the Banda arc-continent collision caused uplift of Rote and Savu at rates of 1-2 mm/yr over the past 3 Ma.

Arc–continent collision is a significant plate boundary process that results in crustal growth. Since the early stages of evolution are often obscured in mature orogens, more complete understanding of the processes involved in arc–continent collision require study of young, active collision settings. The Banda Arc presents an exceptional opportunity to study a young arc–continent collision zone. This thesis presents aspects of the geology and geochronology of Ataúro and the Aileu Complex of Timor-Leste, and the tectonics of the Banda Arc. / U–Pb dating of detrital zircons from the Aileu Complex by LA-ICPMS show major age modes at 270–440 Ma, 860–1240 Ma and 1460–1870 Ma. The youngest zircon populations indicate a maximum depositional age of 270 Ma. The detrital zircon age populations and evidence for juvenile sediments within the sequence favours a synorogenic setting of deposition of sediments sourced from an East Malaya – Indochina terrane. / Previous uncertainty in aspects of the cooling history for the Aileu Complex is resolved with 39Ar/40Ar geochronology of hornblende. Cooling ages of 6–10 Ma are established, with the highest metamorphic grade parts of the Complex yielding the older ages. Cooling ages of 10 Ma imply that metamorphism of the Aileu Complex must have commenced by at least ~12 Ma. Metamorphism at this time is attributed to an arc setting rather than the direct result of collision of the Australian continent with the Banda Arc, an interpretation consistent with the new provenance data. / Geological mapping of Ataúro, an island in the volcanic Banda Arc north of Timor, reveals a volcanic history of bi-modal subaqueous volcanism. 39Ar/40Ar geochronology of hornblende from dacitic lavas confirms that volcanism ceased by ~3 Ma. Following the cessation of volcanism, coral reef marine terraces have been uplifted to elevations of 700 m above sea level. Continuity of the terraces at constant elevations around the island reflects regional-scale uplift most likely linked to sublithospheric processes such as slab detachment. / North of Timor, the near complete absence of intermediate depth seismicity beneath the inactive segment of the arc is attributed to a slab window that has opened in the collision zone and extends to 350 km below the surface. Differences in seismic moment release around this slab window indicate asymmetric rupture, propagating to the east at a much faster rate than to the west. If the lower boundary of this seismic gap signifies the original slab rupture then the slab window represents ~4 m.y. of subsequent subduction and implies that collision preceded the end of volcanism by at least 1 m.y. / Variations in seismic moment release and stress state across the transition from subduction of oceanic crust to arc–continent collision in the Banda Arc are investigated using earthquake catalogues. It is shown that the slab under the western Savu Sea is unusual in that intermediate depth (70–300 km) events indicate that the slab is largely in down-dip compression at this depth range, beneath a region of the arc that has the closest spacing of volcanoes in the Sunda–Banda arc system. This unusual state of stress is attributed to subduction of a northern extension of the Scott Plateau. Present day deformation in the Savu Sea region may be analogous with the earliest stages of collision north of Timor.

Chapter 1-2:The Cassini RADAR mapper has imaged elevated blocks and mountains on Titan we term ‘ridges’. Two unresolved problems regarding Titan's surface are still debated: what is the origin of its ridges and was there tectonic activity on Titan? To understand the processes that produced the ridges, in this study, (1) we analyze the distribution and orientation of ridges through systematic geomorphologic mapping and (2) we compare the location of the ridges to a new global topographic map to explore the correlation between elevation and ridges and the implications for Titan's surface evolution. Globally, the orientation of ridges is nearly E-W and the ridges are more common near the equator than at the poles, which suggests a tectonic origin for most of the ridges on Titan. In addition, the ridges are found to preferentially lie at higher-than-average elevations near the equator. We conclude the most reasonable formation scenario for Titan's ridges is that contractional tectonism built the ridges and thickened the icy lithosphere, causing regional uplift. The combination of global and regional tectonic events, likely contractional in nature, plus enhanced fluvial erosion and sedimentation near the poles, would have contributed to shaping Titan's tectonic landforms and surface morphology to what we see today. However, contractional structures (i.e. thrusts and folds) require large stresses (8~10 MPa), the sources of which probably do not exist on Titan. Liquid hydrocarbons in Titan's near subsurface must play a role similar to that of water on Earth and lead to fluid overpressures, which enable contractional deformation at smaller stresses (< 1MPa) by significantly reducing the shear strength of materials. We show that crustal conditions with enhanced pore fluid pressures on Titan favor the formation of thrust faults and related folds, in a contractional stress field. The production of folds, as on Earth, is facilitated by the presence of crustal liquids to weaken the crust. These hydrocarbon fluids have played a key role in Titan's tectonic evolutionary history, leaving it the only icy body on which strong evidence for contractional tectonism exists. Chapter 3: Arthur Wichmann's ‘Earthquakes of the Indian Archipelago’ documents several large earthquakes and tsunami throughout the Banda Arc region that can be interpreted as mega-thrust events. However, the source regions of these events are not known. One of the largest and well-documented events in the catalog is the great earthquake and tsunami affecting the Banda islands on 1 August 1629. It caused severe damage from a 15-meter tsunami that arrived at the Banda Islands about a half hour after violent shaking stopped. The earthquake was also recorded 230 km away in Ambon, but no tsunami is mentioned. This event was followed by at least 9 years of uncommonly frequent seismic activity in the region that tapered off with time, which can be interpreted as aftershocks. The combination of these observations indicates that the earthquake was most likely a mega-thrust event. We use an inverse modeling approach to numerically reconstruct the tsunami, which constrains the likely location and magnitude of the 1629 earthquake. Only linear numerical models are applied due to the low-resolution of bathymetry in the Banda Islands and Ambon. Therefore, we apply various wave amplification factors (1.5 to 4) derived from simulations of recent, well-constrained tsunami to bracket the upper and lower limits of earthquake moment magnitudes for the event. The closest major earthquake sources to the Banda Islands are the Tanimbar and Seram Troughs of the Banda subduction/collision zone. Other source regions are too far away for such a short arrival time of the tsunami after shaking. Moment magnitudes predicted by the models in order to produce a 15 m tsunami are Mw of 9.8 to 9.2 on the Tanimbar Trough and Mw 8.8 to 8.2 on the Seram Trough. The arrival times of these waves are 58 minutes for Tanimbar Trough and 30 minutes for Seram Trough. The model also predicts 5 meters run-up for Ambon from a Tanimbar Trough source, which is inconsistent with the historical records. Ambon is mostly shielded from a wave generated by a Seram Trough Source.We conclude that the most likely source of the 1629 mega-thrust earthquake is the Seram Trough. Only one earthquake > Mw 8.0 is recorded instrumentally from the eastern Indonesia region although high rates of strain (50-80 mm/a) are measured across the Seram section of the Banda subduction zone. Enough strain has already accumulated since the last major historical event to produce an earthquake of similar size to the 1629 event. Due to the rapid population growth in coastal areas in this region, it is imperative that the most vulnerable coastal areas prepare accordingly.

Petrologic, structural and age investigations of the Lolotoi Complex of East Timor indicate that it is part of a group of thin metamorphic klippen found throughout the region that were detached from the Banda forearc and accreted to the NW Australian continental margin during Late Miocene to Present arc-continent collision. Metamorphic rock types are dominated by (in order of greatest to least abundance), greenschist, graphitic phyllite, quartz-mica schist, amphibolite and pelitic schist. Mineral, whole rock, and trace element geochemical analyses of metabasites indicate that protolith compositions are consistent with tholeiitic basalt and basaltic andesite with mixed MORB and oceanic arc affinities. Metapelitic schist compositions are consistent with mafic to intermediate oceanic to continental arc provenance. Geothermobarometric calculations show peak metamorphic temperatures in pelitic rocks range from 530°C to 610°C for garnet-biotite pairs and peak pressures of 5 to 8 kbar for garnet-aluminosilicate-quartz-plagioclase assemblages. Analyses of amphibole in amphibolites yield temperatures of 550°C to 650°C and pressures of 6 to 7 kbar. Lu-Hf analyses performed on garnet samples from two massifs in East Timor yielded four ages with a mean of 45.36 ± 0.63 Ma, which is interpreted to represent the approximate age of peak metamorphism. Detrital zircons from one amphibolite sample in East Timor yields a bimodal U-Pb age distribution of 560 Ma and 80 Ma, indicating deposition occurred after the 80 Ma closure of the zircon grains. The sequence of deformation as indicated by field measurements is similar to that reported from other klippen throughout the Timor region. Contact relationships with adjacent units indicate that the metamorphic terrane is in thrust contact with underlying Gondwana Sequence rocks. Overlying the metamorphic rocks are Asian affinity volcanic and sedimentary cover units found mostly in normal fault contact on the edges of Lolotoi Complex klippen. Geochemical, age, petrological and structural data imply the Lolotoi Complex formed part of the eastern Great Indonesian arc, which began to collapse in the Eocene, was incorporated into the Banda arc in the Miocene, and accreted to the Austrailian continental margin from Pliocene to Present.