We present an overall analysis of the recent seismic activity occurred in the Adriatic Sea region, a strongly debated sector of the Mediterranean area, where several authors have proposed different models of plate configuration and kinematics. In the past, seismic investigations of this marine area have been strongly hampered by non-optimal network geometries, but data quality increase and recent methodological improvements lay the groundwork to attempt more accurate analyses including proper evaluations of result reliability. On these grounds, we investigated the seismic activity of the last decades by means of new hypocenter locations, waveform inversion focal mechanisms and seismogenic stress fields. We used the Bayloc non-linear probabilistic algorithm to compute hypocenter locations for the most relevant seismic sequences by carefully evaluating location quality and seismolineaments reliability. We also provided an updated database of waveform inversion focal mechanisms including original solutions estimated by applying the waveform inversion method Cut And Paste and data available from official catalogs. Then, focal mechanism solutions have been used to estimate seismogenic stress fields through different inversion algorithms. Seismic results indicate a relevant degree of fragmentation and different patterns of deformation in the Central Adriatic region. In particular, our analyses depicted two NW-SE oriented, adjacent volumes: (i) a pure compressive domain with NNE-trending axis of maximum compression characterizes the northeastern volume where the seismic activity occurs on W-to-NW oriented seismic sources; (ii) a transpressive domain with NW-trending axis of maximum compression characterizes the southwestern sector where thrust faulting preferentially occurs on ENE-to-NE oriented planes and strike-slip faulting on E-W ones. Joint evaluation of seismic findings of the present study and kinematic models proposed in the literature indicates just in the Central Adriatic region the presence of a broad deformation zone, accommodating a still evolving fragmentation of the Adriatic domain in two blocks rotating in opposite directions. On these grounds, the obtained results not only furnish new seismological evidence supporting the "two-blocks model" proposed by previous authors, but they also provide additional constraints, useful for better understanding and modeling the seismotectonic processes occurring in the Adriatic region.

Data availability

Data used in the present study were collected from catalogs and bibliographic sources indicated in detail in the article. Waveform inversions performed in this study used data available in the database EIDA, http://orfeus-eu.org/webdc3/ (accessed February 2022)

中文翻译：

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亚得里亚海地区的地震变形

我们对最近发生在亚得里亚海地区的地震活动进行了全面分析，亚得里亚海地区是地中海地区备受争议的地区，几位作者提出了不同的板块配置和运动学模型。过去，该海域的地震调查受到非最佳网络几何形状的严重阻碍，但数据质量的提高和最近方法学的改进为尝试更准确的分析奠定了基础，包括对结果可靠性的适当评估。基于这些理由，我们通过新的震源位置、波形反演震源机制和发震应力场研究了过去几十年的地震活动。我们使用 Bayloc 非线性概率算法通过仔细评估位置质量和地震线可靠性来计算最相关地震序列的震源位置。我们还提供了一个更新的波形反演震源机制数据库，包括通过应用波形反演方法“剪切和粘贴”估算的原始解以及来自官方目录的数据。然后，震源机制解已被用于通过不同的反演算法来估计地震应力场。地震结果表明中亚得里亚海地区存在一定程度的碎裂和不同的变形模式。特别是，我们的分析描绘了两个 NW-SE 导向的相邻卷：(i) 具有最大压缩的 NNE 趋势轴的纯压缩域表征东北体积，其中地震活动发生在 W 到 NW 方向的地震源上；(ii) 具有 NW 向最大压缩轴的压压域是西南部分的特征，其中逆冲断层优先发生在 ENE 到 NE 方向的平面上，走滑断层发生在 EW 方向上。对本研究的地震发现和文献中提出的运动学模型的联合评估表明，仅在亚得里亚海中部地区存在一个广泛的变形区，在两个相反方向旋转的块体中容纳了亚得里亚海域仍在演变的破碎。基于这些理由，所获得的结果不仅为支持“两块体模型”提供了新的地震学证据

数据可用性

本研究中使用的数据是从文章中详细说明的目录和书目来源中收集的。本研究中进行的波形反演使用了数据库 EIDA 中的可用数据，http://orfeus-eu.org/webdc3/（2022 年 2 月访问）