A multi-event paleoseismic record from the northern Alpine Fault at Marble Hill, Aotearoa New Zealand
Bibliographic record
Abstract
Multi-event paleoseismic records are essential for understanding fault behaviour, characterising seismic hazard, and testing earthquake simulator models. The reverse dextral Alpine Fault is the main Australian-Pacific plate boundary structure through the central and southern South Island of Aotearoa New Zealand. While the paleoseismic record of the southern and central sections is relatively well-understood, in contrast, the northern section of the Alpine Fault (AF-NS), adjacent to the distributed Marlborough Fault System (MFS) remains understudied. We present new on-fault paleoseismic data from Marble Hill, a well-known offset alluvial terrace site next to the Maruia River, including results from three trenches and four pits. Dating of deposits comes from radiocarbon and infra-red stimulated luminescence (IRSL) techniques. IRSL dates indicate that the degradational terrace sequence at Marble Hill spans the last ~2000 years. Trenches reveal evidence for up to four recent paleoearthquake ruptures with timings of ~1595–1834 (MRE, most recent event), 952–1406 (E2), 706–933 (E3), and 246–736 CE (E4). Preservation of this record has been possible due to avulsion with ensuing incision and degradation of the Maruia River toward its current north-westerly course. A local AF-NS recurrence interval of 413 ± 103 yr is derived from the three closed paleoearthquake intervals between the MRE and E4. The three youngest events are associated with ~1.3 m (MRE), and 10.7 ± 1.3 m dextral displacement split between E2 and E3. This is the first multi-event timing and slip record from the AF-NS and our results highlight the inadequacies of earlier work that targeted only the MRE. A longer recurrence interval (than for the central and southern sections) and variable displacement per event at the Marble Hill site are indicative of its location along the Alpine Fault, implying a more complex rupture record along the AF-NS adjacent to the MFS and transitioning toward the Wairau Fault.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.013 | 0.004 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".