GNGTS 2013 - Atti del 32° Convegno Nazionale

related to water and land: for example, changes of the water level in wells, different springs flow, burning and cracking of the land. Today, living in towns, it may be difficult to daily catch these “observable” phenomena; however, they may be quantized, and also other parameters, which cannot be detected without instruments, are monitored. (Riggio and Santulin, 2012). All kinds of seismic precursors are a unified reaction of the earthquake preparation process, although the observed physical quantity of precursor is different from each other. The process of occurrence and preparation of large earthquake influences the characteristic of the anomaly, including the trend anomalies observed that last one year or several years in the phase of long-medium term before a large earthquake occurs, and the abrupt anomalis observed in the short term and impending phase. (Zhang et al. , 1996). In some works of Chinese researchers of the 90’ is already reported the influence of the type of mechanism of the earthquake on the characteristics of the anomaly. Between the various precursors observed, a group is constituted by variations of the physical-chemical characteristics of the fluids circulating in the Earth’s crust. Changes in the fluids chemical composition, which occur as transient phenomena, can indeed provide information about the status of crustal deformation. The relationship between the tectonic structures, the crustal deformation and physic-chemical characteristics of the circulating fluid is in many cases supported by studies and measures that allow correlations between causes and variations of these parameter. This paper describes the activities carried out in the framework of the project DPC – INGV: Short term earthquake forecasting - Research Unit 1 (U.R.1): Monitoring of deep seated underground fluids. The U.R.1 had the task of studying the state of the art of observable parameters related to underground fluids taking into account their history and the studies done over the years. Inside the U.R.1, a separate chapter was created for the “Radon” as it is one of the most monitored parameters with different methods and with different types of instruments. Activities performed. The first task was to make a detailed and well-documented analysis of the existing literature on the subject. The material available was very consistent since the radon was identified as a possible earthquake precursor back in the 1920s. The aim of this collection was also to establish in which cases of failed predictions, the observed radon had been considered. In fact, for disastrous earthquakes of the past, an evaluation of the individual observable was not made, but only a general “Forecast” evaluation, made according to numerous parameters. The aim of the study was to gather all the information concerning the role of radon in the “earthquake prediction”, distinguishing between the various acquisition methods. The Kobe earthquake that is considered as a “Forecast Failure” was actually preceded by radon anomalies in the water, but since it was not accompanied by an activity of foreshocks, the signal was not taken into account. The Haicheng earthquake in China was the real earthquake predicted because all protocols were satisfied (abnormal fluid and foreschoks). Instead, the Tangshan earthquake, which occurred in China a year and half after that of Haicheng is reported as a failure of the “prediction”. In fact, even if variations in the content of radon in the water of 27 wells, distant as 300 km, were recorded before and after the earthquake, the absence of foreshocks did not allow to combine all the parameters required to issue an evacuation order (Santulin and Riggio, 2013). The reviewwas concludedwith the identification of all the scientific and amatorial institutions on the national territory that hold possible time series related to radon measurements in soil, in water and in air, and other additional parameters (chemical ones, for water and weather). The second product of the project was a database with all the existing data received, after that an official letter of request was send to insert the same data in the database. The statistical data related to the requests made, the data received and their spatial distribution are shown in Tab. 1 and Fig.1. 124 GNGTS 2013 S essione 2.1