|
Galadini F., Tertulliani A., 2025. Il terremoto di Rosciolo dei Marsi del 24 febbraio 1904 (Abruzzo, Italia centrale): revisione dei dati e nuove acquisizioni storiche. Quaderni di Geofisica, 196. https://doi.org/10.13127/qdg/196 
Abstract
Il terremoto del 24 febbraio 1904, con epicentro nel settore nordoccidentale della Marsica (Abruzzo), è presente nei cataloghi sismici CFTI5Med e CPTI15 con magnitudo Me 5.6 e Mw 5.68, rispettivamente. Le valutazioni si basano sulla stima delle intensità pubblicata nel catalogo CFTI1, con un valore massimo, I 9 MCS, attribuito all’abitato di Rosciolo, frazione di Magliano de’ Marsi (AQ). L’interesse per questo evento sismico da parte della comunità scientifica dell’epoca, al momento dell’accadimento piuttosto limitato, fu risvegliato dalle ricerche avviate a seguito del catastrofico terremoto del 1915 che ebbe, tra le località più colpite, alcune di quelle già danneggiate undici anni prima. La corretta stima degli effetti del 1904 era però ormai condizionata dalla scarsa rilevanza dei dati disponibili, mancando peraltro informazioni da sopralluoghi di sismologi e geologi. Di conseguenza, le prime valutazioni ebbero, tra i principali riferimenti, le notizie sulla zona terremotata fornite da inviati e corrispondenti dei giornali, pubblicate tra marzo e aprile 1904 – resoconti in alcuni casi contraddittori, che rendevano immagini di distruzione non del tutto compatibili con quanto desumibile anche da altre fonti. In occasione del 120° anniversario e in concomitanza con alcune manifestazioni in località allora danneggiate, si è ritenuto opportuno avviare un nuovo studio per valutare gli effetti del terremoto, mediante la revisione di quanto già in letteratura, la lettura critica delle informazioni pubblicate in ventidue giornali dell’epoca, l’analisi di documenti consultabili presso archivi romani e abruzzesi. L’indagine ha suggerito un sensibile ridimensionamento dell’entità dei danni, evidenziato dall’intensità massima, attribuita a Rosciolo dei Marsi, I 8 (EMS-98 e MCS), e dalla stima degli effetti nel poco meno danneggiato abitato di Magliano de’ Marsi (I 7.5 EMS-98 e MCS). Conseguenza di questa rivalutazione è la riduzione della magnitudo, qui valutata con Mw 5.18. Lo studio ha altresì affrontato il problema della caratterizzazione della sequenza sismica, già oggetto di pubblicazioni del XX secolo, consentendo la definizione di un maggiore numero di eventi successivi al principale (77), rispetto a quanto finora noto (59). A quattordici di queste repliche sono riconducibili importanti risentimenti, anche con effetti al di sopra della soglia del danno. Altri argomenti del presente studio riguardano le ipotesi sismogenetiche – affrontate sia in una prospettiva storica, menzionando i richiami dell’epoca sull’origine delle scosse che avevano interessato la Marsica, che discutendo le attuali interpretazioni in materia di faglia causativa – e la riedificazione successiva al 1904, argomento di interesse in considerazione del fatto che i fabbricati a suo tempo danneggiati subirono, undici anni dopo, l’assai più gravosa prova del terremoto del 1915.The earthquake occurred in the NW sector of the Marsica region (Abruzzi Apennines, central Italy) on 24 February 1904 has been parametrized in the modern Italian seismic catalogues with magnitude Me 5.6 (CFTI5Med [B1: Guidoboni et al., 2018]) and Mw 5.68 (CPTI15 [B1: Rovida et al., 2022]). This event damaged a region which, differently from the adjacent L’Aquila sector of the Apennines, was not characterized by a significant seismic history. The scientific and popular view of a territory seismically negligible was still further contradicted eleven years later, on 13 January 1915, when the same area was struck by a catastrophic event (Mw 7.08 [B1: Rovida et al., 2022]), responsible for new damage (in some cases complete destruction) of the settlements already damaged in (and repaired after) 1904. Later on, the geological investigations since the 1970s showed that the above mentioned earthquakes had occurred in a sector of the Apennines affected by recent and current fault activity [B1: Bosi, 1975; Bertini e Bosi, 1976; Giraudi, 1986; 1988; Serva et al., 1986; Galadini e Messina, 1994; Michetti et al., 1996; Galadini e Galli, 1999; Cavinato et al., 2002; Galli et al., 2012; Gori et al., 2017a; Patruno e Scisciani, 2021]. Some of the cited works deal with the 30Km long fault emerging along the western and northern borders of the Fucino basin, considered as the causative source of the 1915 earthquake (Figure 1). In short, the modern geological and geomorphological knowledge indicates that the occurrence of strong seismic events would not be unexpected in this part of the central Apennines. The characteristics of the 1904 earthquake summarized in the above-mentioned parametric catalogues are based on a study published in the 1990s (i.e., the catalogue CFTI1 [B1: Boschi et al., 1995]), giving a distribution of the intensities according to the MCS macroseismic scale. Intensity data from that analysis indicate that the mainshock caused significant damage to several villages (Rosciolo dei Marsi, I 9 MCS; Magliano de’ Marsi, I 8-9 MCS; Cappelle, Gallo, Poggio Filippo, San Donato, Sant’Anatolia, I 8 MCS). This estimation was mainly based on reports of the effects published at the beginning of the 20th century [B1: Monti, 1906; Cavasino, 1914], the critical reading of some newspapers of that time and of the telegrams sent from authorities of the damaged region to the Ministry of the Interior. However, information published at the beginning of the 20th century was not based on surveys made by seismologists or geologists and the recent and current research has not uncovered technical reports by scientists among the sparse documents regarding the 1904 seismic event. The first estimations on the earthquake effects benefited of short communications sent by people living in the region struck by the shocks (sometimes mayors of the damaged small towns) to Ufficio Centrale di Meteorologia e Geodinamica at Rome and of the descriptions of the effects by special correspondents of newspapers. A picture of almost complete destruction can be derived from many journalistic passages, due to the literary emphasis used by newsagents to describe the consequences of the earthquake. These newspaper views were almost uncritically included in the old scientific publications above mentioned, favoring the estimation with high MCS intensity values also in the modern contributions which considered the old literature to quantify the earthquake effects. These aspects made a new study of the 1904 earthquake necessary, and the opportunity was given by recent considerations, discussions and activities on the 120th anniversary of the seismic event, commemorated in two of the villages damaged at that time (Rosciolo dei Marsi and Scurcola Marsicana). Our investigation was based on: i) the critical review of the available literature, especially of the contributions published more than one century ago; ii) the reading of a greater number of newspapers compared to those used in previous studies (i.e., 18 newspapers for the period February-July 1904 and 4 newspapers for the period February 1904-January 1905); iii) the analysis of historical documents from archives at Rome and in the Abruzzi region (Archivio di Stato dell’Aquila, Archivio Storico Diocesano dei Marsi at Avezzano, Archivio Storico del Comune di Magliano de’ Marsi, Archivio Centrale dello Stato at Rome, Archivio Macrosismico dell’Istituto Nazionale di Geofisica e Vulcanologia at Rome). The already available and the uncovered documentary materials permitted to interpret some journalistic views as excessive and, therefore, to consider estimations in the old publications as not fully reliable. Presently, we believe that intensities (EMS-98 and MCS scales) should be attributed to the most damaged localities as follows: Rosciolo dei Marsi, I 8 EMS and MCS; Magliano de’ Marsi, I 7.5 EMS and MCS; Cappelle, Gallo, Poggio Filippo, San Donato, Sant’Anatolia, I 7 EMS and MCS; Scanzano I 6.5 EMS and MCS; Scurcola Marsicana, I 6 EMS and 6.5 MCS; Marano, Massa d’Albe, I 6 EMS and MCS (Table 1; Figure 10). The intensities reported in Table 1 defined new parameters summarizing the characteristics of the earthquake, Io 7.5, Ix 8, Mw 5.18 (Table 2), significantly lower than those available in the catalogues mentioned above. The collected information also permitted to define a list of aftershocks made of 77 events (Table 3), occurred between 25 February and 31 December 1904. Though representing a partial view of the whole seismic sequence, this new list defines a significant increase of the number of aftershocks (59) already reported in the publication by Molin et al. [B1: 1999]. Fourteen minor events (six of which were already included in the above-mentioned catalogue CPTI15, basing on the previous study by Molin et al. [B1: 1999]) have been considered as strong enough to have been responsible for further damage (i.e., Ix ≥ 5 EMS‐98), as indicated by the studied journalistic sources or by archive documents. We refer to the shocks occurred on: 25 February (00:29), 26 February (00:45), 28 February (00:30), 1 March (01:52), 3 March (18:55), 10 March (04:21), 11 March (13:25), 15 March (01:15), 20 March (05:50; 07:50), 29 March (08:30), 6 April (19:25), 7 April (19:00), 13 April (05:57). The Intensity datapoints of the strong aftershock occurred on 25 February (Mw 4.4) are plotted in Figure 11. As for the seismogenic aspects, the 1904 earthquake has been attributed to the northernmost section of the Fucino fault, corresponding to that defined as Magnola Mts.-Mt. Velino fault (Figure 15) [B1: Galadini et al., 1998; Valentini et al., 2019]. This attribution was based on the consistency of the intensity datapoints distribution with the attitude of the fault. This purely geometric relationship has not changed after the revision of the earthquake, since net of the different intensity values, the geometry of the distribution is comparable to that available until now. However, the attempt to link the 1904 earthquake to the mentioned fault must consider the decrease of the magnitude proposed in our study. The association of a moderate magnitude earthquake to a specific fault potentially responsible for M 7 seismic events is not without pitfalls. Considering the less significant area of the seismogenic rupture, we cannot exclude that the studied earthquake was originated by a secondary fault not emerging at surface. Another aspect discussed in this study is represented by the repairs following the 1904 earthquake. This concerns the vulnerability of the buildings at Rosciolo dei Marsi, i.e., the most damaged village (I 8 EMS-98 and MCS). After the seismic event, many iron tie rods (and some buttresses) were placed on buildings damaged by the shocks of the seismic sequence and affected by precarious stability conditions (Figure 12). Contemporary eyewitnesses considered (and current residents still consider) these interventions as the main reason for a damage in 1915 significantly lower than that observed in the nearby villages. Paradoxically, the highest damage in 1904 was the reason for the necessary repairs at Rosciolo which decreased the vulnerability of the buildings and contributed to mitigate the impact of the 1915 earthquake. Still today, Rosciolo maintains original buildings of the past centuries with interesting, though partly abandoned, architectural emergences. By contrast, less widespread distribution of repairs, or no intervention at all, characterized other less damaged villages, with the consequence that buildings with very high vulnerability faced the test of the strong 1915 shaking with a catastrophic outcome.
|
Nell'archivio ci sono In the archive there are 78 terremoti provenienti da questo studio: earthquakes considered from this study:  non parametrizzatinot determined falsifakeClicca sulla riga per individuare il terremoto sulla mappa o sulla lente per ottenere più informazioni.Click the row to highlight the earthquake on the map or the lens to obtain more information.
|
