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Observations since 1998 have revealed that repeating earthquakes, and particularly small repeating earthquakes, occur less often than expected given their seismically derived slip and the regional fault slip rate. Here we test the hypothesis that small repeaters occur infrequently because they occur on fault segments or strands with low slip rates. We analyze the recurrence interval‐moment scaling of earthquake sequences near Parkfield, California. We find that closely spaced sequences, which likely occur on the same fault strand and respond to the same slip rate, follow a M013 scaling consistent with seismic slip rates while widely spaced sequences, which likely occur on different strands, follow a M00.17 scaling consistent with the previous counterintuitive observations. These results suggest that spatially varying slip rates could create the M00.17 recurrence interval scaling, though we cannot exclude other explanations. Plain Language Summary: We study repeating earthquakes, which repeatedly rupture part of a fault. Previous observations have shown that the cumulative slip in repeating earthquakes is smaller than the slip estimated from geological observations. This difference in slip means that the intervals between earthquakes are longer than expected, especially for smaller earthquakes. We examine whether the time between repeating earthquakes is long because small repeating earthquakes occur on a collection of shorter fault strands that exist within and contribute to the larger fault regime. We suggest that smaller earthquakes are more likely to occur on shorter fault strands and that shorter strands are likely to have lower slip rates than longer strands. Earthquake patches on shorter strands may be loaded slowly, so that the small earthquakes occur less often than expected. To test this possibility, we examine whether earthquakes that occur close together respond to the same slip rate. We find that closely spaced earthquakes do respond to the same slip rate, and widely spaced earthquakes respond to different slip rates. Our observations indicate that small repeating earthquakes may occur on short low slip rate fault strands. Key Points: We explore why small repeating earthquakes have surprisingly long recurrence intervalsFind that the scaling between recurrence interval and moment differs between closely and widely spaced earthquake sequencesSpacing‐dependent recurrence interval scaling could result from spatially variable or fault strand‐dependent slip rates [ABSTRACT FROM AUTHOR]

Estimating slip rates of active faults is critical not only for assessing of seismic potential of these structures but also for understanding their geodynamics. The North Anatolian Fault (NAF) forms the boundary between Anatolia and Eurasia with the total slip rate of 24.6±0.2 mm/yr, deduced by GPS-based elastic block modelling. However, the quantification of total strain along the NAF is also a challenging problem where the fault leaves its single going narrow deformation zone and bifurcates into two strands (Düzce and Mudurnu Valley Segments) to the west of Bolu. In order to reveal the long term slip rate of the Mudurnu Valley Segment, we conducted a new slip rate study at the Taşkesti Site to the south of the Almacık Block by using high resolution UAV-based DEMs and multiple geochronological techniques. Our geological mapping shows a depositional river terrace, having a dextral offset of 52-62 metres where its age is constrained to 5.79±0.13 ka (radiocarbon) as an upper boundary and 5.36±0.19 ka (OSL) as a lower boundary. By using a boxcar uncertainty model, we calculate 10.3 +2.4/-2.3 mm/yr as the Holocene slip-rate of the Mudurnu Valley Segment. We compare our results with other nearby geodetic, and other geologic rate studies to determine (a) the total strain accumulation along the western section of the NASZ and (b) to understand the ratio of strain partitioning between Düzce and Mudurnu Valley segments. Our preliminary results strongly suggest strain partitioning between parallel/sub-parallel elements of the North Anatolian Shear Zone. The implication of this study also contributes to an understanding of the spatial and temporal slip behaviours of other major continental strike-slip faults. [ABSTRACT FROM AUTHOR]