## 13 Discussions and Conclusions Regarding Gaps and Areas of Improvement in the System
It would not be realistic at all to expect that rupture heterogeneities, the variation of the slip and where the highest (tsunamigenic) slip is concentrated in a given earthquake could be captured realistically in a pre-calculated tsunami scenario database or in real time. Moreover, pre-calculated deterministic tsunami databases may lead to erroneous results for tectonic regions where the dominant fault orientation cannot be determined easily due to a lack of instrumental data of geologic evidence, which is an important limitation for faults buried under the seabed. Computational advancements may allow the realization of near-real-time tsunami modeling in an operational tsunami warning system with an additional delay for the initial tsunami warning of less than one minute. However, the real added value of near-real-time modeling-based tsunami warnings for a region where the sources are mostly local or near-field is not the initial tsunami early warning, but rather the assessment and evaluation of the tsunami that is generated. The availability of such a system could allow a tsunami warning center to dynamically compare sea level observations, especially where the spatial density is high, and to make use of the updated source parameters on the spot to rapidly update and improve the tsunami forecast after the initial tsunami warning has been disseminated [42]. While recent efforts have focused on the use of probabilistic methods [43] to overcome the uncertainties associated with the deterministic approaches, whether through a decision matrix, pre-calculated tsunami scenario databases or near-real-time tsunami modeling, the real problem is on the side of the downstream component [44], namely the civil protection authorities, who have the responsibility of initiating tsunami evacuation orders. The uncertainty in the upstream component of the tsunami warning system cannot be avoided, unless all TSPs are synchronized in such a way that a unique warning message could be produced, which would correspond to an ill-formulization of the interoperability concept. Regardless of the type or content of the tsunami warning message, it is the analysis and interpretation capability of the message recipient as either a NTWC or TWFP that plays the key role in saving lives. It is also likely that divergent information from different TSPs could very well serve as a useful indicator of the degree of uncertainty for the end-user, meaning the problem could then be formulated so that SOPs could be followed by the message recipient [44]. Hence, efforts should focus on capacity-building programs targeting civil protection authorities or government agencies with national responsibility, such as NTWCs or TWFFs. The classical tsunami warning methodology depends on the reliable identification of the location, depth and magnitude of an earthquake, which dictates >7 min for the issuance of the initial tsunami warning with acceptable reliability, which may be still late for some coastal locations in the Eastern Mediterranean and Aegean Seas, where the tsunamigenic earthquake sources are located very near to the shoreline, as experienced once more during the 30 October 2020 Mw 6.9 earthquake. Local tsunami warning systems [33; 34; 35] triggered by the exceedance of a pre-determined acceleration value could reduce the warning time down to <1 min and could help the evacuation process, especially in coastal communities with low awareness of the tsunami threat after a strong earthquake.