## 1 Introduction
### Study Area  
The 2021 Tajogaite eruption occurred at the upper western flank of the Cumbre Vieja (Figure 1), located on La Palma Island, which is the most active volcano of the seven Canary Islands. Repeated phases of island construction during eruptions and destruction by lateral collapses characterize the evolution of La Palma [26]. Two polygenetic volcanic complexes shape the Island: on the northern part, a large circular volcano and uplifted ocean crust complex is dominant, whereas on the southern part, the Cumbre Vieja is an elevated volcanic rift most active in written history [26]. The northern near circular volcano evolved during the Pliocene by superpositioning of four distinguished volcanic structures, from which one is a submarine and the other three are subaerial volcanoes. The three subaerial volcanoes are named Garafia (formed 1.77 to 1.20 million years ago), Taburiente-Cumbre Nueva (formed 0.89 Ma) and Bejenado (formed 0.4 Ma) [27]. The northern edifice has been affected by several mass-wasting events, possibly catastrophic, which have encarved the deeply incised morphology of the Taburiente-Cumbre Nueva (560 ka) and later affected the Cumbre Nueva rift zone. The southern volcano edifice is the youngest (123 ka) and, thus, the area where the last six historical eruptions were recorded on the island in the last 500 years [27]. Cumbre Vieja is a rift oriented north to south (N-S) with an altitude of ~1950 m above sea level. Some of the most recent events were the San Juan eruption in 1949, which created three eruptive vents (Duraznero, Llano del Banco and Hoyo Negro), and the Teneguia Eruption in 1971 [28].  
Dikes and sills can be found all over the island and usually range from 0.2 to 1.2 m wide [26; 29]. Shallow intrusions at Cumbre Vieja show topographical irregularities and produce prominent structural features, forming the volcanic ridge associated with faults, fissures, and vents, many of which are aligned along the N-S directed rift zone [19; 27; 30]. Furthermore, some less-expressed structural features, or weak rift zones, in the northern sector of the Cumbre Vieja diverge NE-SW and NW-SE [19; 31]. The 2021 erupting craters follow a NW-SE direction, as will be detailed further below.  
Following 50 years of quiescence, a new unrest period with intense seismic activity began on 11 September 2021 and continued through the 85 days of the eruption [32; 33]. During the 85-day eruption period, several vents opened and nested on the elongated cone on the western flank of Cumbre Vieja, near to the faulting system of 1949 [32; 33; 34]. It was estimated that the Tajogaite cone was built up to 187 m from its base due to the accumulation of tephra (ash, lapilli and larger bombs) and lava flows [35]. The eruption also produced constant emission of ash, steam, volcanic gasses, and approximately 200 million m\({}^{3}\) of lava [32]. However, more detailed estimates come from drone surveys that suggest a smaller volume of ~180 Mm\({}^{3}\)[35]. The eruption had a Volcanic Explosivity Index of VEI3 [32]. The 2021 Cumbre Vieja eruption presents a unique opportunity to study crater arrangement as an indicator of dike intrusion and its possible link to volcano-technic processes [33].