On the edge of our continents, oceanic crust meets continental crust. At passive margins, those where there is no active tectonics, subduction or transform faulting, these crustal types are connected as sharp continent-ocean boundaries (COB) or as diffuse continent-ocean transition (COT) zones. Passive margins are hard to explore and consequently relatively little is known about their morphology or the processes of their formation. Here we elicit and analyse seismic image interpretations of the passive margin offshore East India conducted by 17 groups of geoscientists to better understand the differences, or lack therein, of COB or COT interpretations of the margin. The group interpretations provide a wide range of margin models, five of which are abrupt COB based and 11 which are diffuse COT based. However, interpretations within the COB set vary in the placement of the boundary line between continental and oceanic crust, the boundary placement lying within the range of interpreted COT zones, with the average COB location falling in the centre of the interpreted COT zones. These crowd-sourced results are then compared with ten published interpretations across the margin, which show COB and COT zones falling in the same area. These findings raise questions as to the real differences in COB and COT models and the geological processes involved in their formation. Considering this, we discuss the implications for passive margin models and the use of Wisdom of Crowds-type approaches in reflecting on both the range of interpretation-based models and in the value of determining ‘average’ model approaches.

Seismic reflection data (normal incidence and wide-angle) are unique assets for Solid Earth Science. They provide critical information about the physical properties and structure of the lithosphere, and are useful to understand the geometry and evolution of the tectonic plates, and for exploration of natural resources, civil engineering, characterization of seismogenic zones and hazard assessment. The resolution of seismic reflection data is highly appreciated for basic and applied Earth Sciences. However, these datasets are logistically complex and expensive to acquire, and their geographical coverage is limited. In addition, legacy seismic reflection data also have an added value as new information can be retrieved by applying new processing approaches. The preservation and dissemination of seismic open access data is an asset to promote accurate and innovative research. Here, we present the Seismic DAta REpository (SeisDARE), which is, to our knowledge, one of the first comprehensive open access online databases that stores seismic data registered with a permanent digital object identifier (DOI). The datasets included here are accessible online and guarantee the FAIR (Findable, Accessible, Interoperable, Reusable) principles of data management, so that each dataset enters into a statistic referencing database and its impact can be measured. This database has been built thanks to a network of several institutions, promoting a multidisciplinary research, and is open for international data exchange and collaborations. SeisDARE includes deep seismic sounding and high-resolution data acquired in the last three decades in the Iberian Peninsula and Morocco. In addition, as result of fruitful collaborations, we are starting to host data acquired worldwide. Our first incorporation of this kind are seismic profiles recorded in Hardeman County, Texas, within the COCORP project. SeisDARE aims to make easily accessible legacy and recently acquired seismic data and establish a framework for future seismic data management plans. The datasets are available at https://digital.csic.es/handle/10261/101879, bringing endless opportunities to the scientific, industrial and educational communities. This research has been funded by EPOS IP 676564, EPOS SP 871121, EIT Raw Materials 17024-SIT4ME and SERA 730900.