# Analysis of Information Availability for Seismic and Volcanic Monitoring Systems: A Review
## 2 Methodology Validation
### Study Selection  
This section is built based on the structure of a systematic review ([PERSON] guide--Section 5. Conducting the review) [20; 21]. From this approach, two criteria identify relevant studies (51 articles) and potentially relevant studies (29 articles), depending on how much they directly contribute to the research questions. Moreover, the third criterion refers to non-relevant studies (130 articles), i.e., those that do not respond to the RQs raised. In addition, duplicate studies were also filtered. This study reviewed inclusion and exclusion criteria, which are essential features to determine the literature review's relevance. The exclusion criteria were:  
* Studies that do not relate to the proposed research objectives;
* Studies that delve into seismic risk management;
* Specific geological studies;
* Studies without peer review. The inclusion criteria are listed below:* Publications in English and Spanish;
* Publications since 2000;
* Publications type: articles (journals, conferences, surveys, SLR), reports, book sections;
* Relevant publications related to: 1. Security of information;
* Availability;
* Data acquisition;
* Algorithms;
* Routing protocols;
* Seismic networks;
* Acquisition and processing systems;
* Data centers;
* Seismic monitoring;
* Seismic stations;
* Components and infrastructure. * Official websites, reports of seismological organizations. A summary of results found with the searching string (outcome, inclusion, and intervention) and selection criteria mentioned above is presented in Table 2. The largest number of articles has been found with the proposed search strings for RQ1 with 1003 articles. Besides RQ2 and RQ3, there are 601 and 334, respectively. On the other hand, combined relevant terms that retrieve more related articles in the string are: seismic data, acquisition, processing, algorithms, and protocols. Concerning databases, Science Direct has more quantity of related articles for this study (39%) in comparison to Scopus (24%), ACM (20%), and IEEE Xplore (17%). The goal of this stage has been to obtain relevant studies, making it necessary to apply a selection based on the inclusion criteria and study quality assessment mainly. With the search results, a more detailed review was made of the potential studies. A first step is to detect duplicate works in our preliminary search because many works are indexed in several repositories. After that, we made classifications based on their relevance to our review according to the following criteria:  
* _Not relevant studies_. Studies that do not contribute to answering research questions RQ1, RQ2, or RQ3. \begin{table}
\begin{tabular}{l l} \hline \hline
**Most Important Terms** & **Search Expression** \\ \hline  & RQ1 \\ \hline _algorithms and protocols related to availability of information_ & seismic data (AND) algorithms (OR) protocols (AND) data acquisition \\ \hline  & seismic networks (AND) algorithms (OR) protocols (AND) availability \\ \hline  & real-time seismic data (AND) algorithms (OR) protocols (AND) seismic networks \\ \hline  & RQ2 \\ \hline _standards, formats, and systems for seismic data acquisition and processing_ & seismic data (AND) formats (OR) standards (AND) acquisition (OR) processing \\ \hline  & seismic monitoring networks (OR) volcanic monitoring networks (AND) formats (OR) standards (AND) acquisition systems (OR) processing systems \\ \hline  & RQ3 \\ \hline _seismic–volcanic monitoring trends for seismic data transmission and redundant seismic networks_ & seismic monitoring networks (AND) data transmission (AND) redundancy \\ \hline  & seismic monitoring networks (OR) volcanic monitoring networks (AND) redundant systems (AND) early warnings \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Structuring search strings. * _Potential relevant studies._ Within this articles group, we identified an indirect relationship between the objective mentioned in RQ1 and the solutions proposed for data transmission assurance in real time.