**3. Tsunami early warning system**

per year, resulting in frequent and large earthquakes [13]. The Japan Trough has a long history of large events, including the 869 Mw 8.3 Jogan, 1896 Ms 7.2 Meiji Sanriku and 1933 Mw 8.4

On 11 March 2011, an earthquake with magnitude of 9.0 off the northeastern coast of Japan triggered a tsunami [6]. The waves reached up to 40 m high and penetrated up to 5 km inland. It caused a great loss of life (~20,000), strong environmental damage and infrastructural destruction. The tsunami has also severely affected the Fukushima nuclear power plant,

One of the major disaster effects that require an especial attention is the environmental damage at the coastal area due to transportation of sediments and debris from ocean to coast and vice versa. For example, during 2004 Sumatra tsunami, the sediment transport and coastal subsi‐ dence associated with the tsunamis had a major impact on urban communities and also in ecosystems. Unfortunately, these types of impact have not been adequately studied because

Several case studies indicated that splay faults are associated with subduction zones in the world [3, 11]. They develop within the sedimentary sequences as sediments being added from the upper plate. The superimposed effect of splay faulting on tsunami wave heights in the near-field has been observed in many mega-tsunami events. In this respect, the 1946 Nankai, 1960 Chilean and 1964 Alaskan earthquakes and tsunamis [8, 14] and the most recent case of

Thus, splay faults can play an important role, in particular, as local hazard, and thus their

At this stage, we do not believe that these faults individually are capable of producing tsunami, but as indicated above, they can play an important role in strengthening the tsunami hazard effect during megathrust ruptures. So, we strongly suggest that this factor should be accounted for a comprehensive tsunami hazard analysis. These factors in addition to the above-men‐ tioned items, if are not implemented accurately, will make the design of an effective tsunami

Mud volcanoes are known from onshore, where erupted water often is methane saturated. These are the result of progressive compression and dewatering of the deep undercompacted, overpressured sequences (at decollement). The world's most notorious mud volcano, Indo‐

Offshore Makran (Northwest Indian Ocean), numerous mud volcanoes have been mapped. There is a direct relationship between mud volcanoes and transform faults. Not all mud

they may have long-term effects both on environment and on the regional economy.

Showa Sanriku events, all of which produced large destructive tsunamis [13].

causing serious risks of contamination from radioactive releases.

*2.2.3. Tsunami major disaster effects*

6 Tsunami

*2.2.4. Factors strengthening the tsunami disaster*

the 2004 Sumatra-Andaman could be mentioned.

identification is important.

early warning system problematic [15].

*2.2.5. Mud volcano (example from Makran)*

nesia's Lusi, destroyed a town in 2006.

The main elements that are required to be considered before any decision to set up an early warning system are frequency, severity, lead time, accuracy, response costs, loss reduction and early warning system cost. A feasibility study needs to be conducted with great precision taking into account also the public education and their awareness to full response.

The current tsunami preparedness policy, which is oriented toward warning and evacuation, needs to be revised worldwide. Coastal cities, ports and marine constructions at tsunami risk are growing and becoming more and more vulnerable to a tsunami impact. Today, we cannot ignore an increasing risk of cessation of sea-port operation, oil platform destruction or coastal devastation. The safe and stable function of sea ports, coastal oil or gas tanks, cold storage, fisheries and other facilities becomes more significant for the economic development of coastal communities. Economic risk management is an important goal, which has to be solved for coastal urban and industrial areas at tsunami risk. Therefore, it is important to engage in dayto-day efforts to improve public awareness, preparedness and regional cooperation to deal with marine natural disasters.
