The Risk of Tsunamis in Mexico

1. Introduction

A tsunami has been defined as “a series of travelling waves of extremely long length and period, usually generated by disturbances associated with earthquake occurring below or near the ocean floor… Volcanic eruptions, submarine landslides, and coastal rock falls can also generate tsunamis, as can a large meteorite impacting the ocean” [1]. Also, tsunamis may be regarded as low frequency events but with high impacts in terms of human/infrastructure/economic losses. Their power of destruction has been more than evident in recent years [2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. It is believed that from the time period between 1998 and 2017, the losses inflicted by tsunami disasters were a total of US$280 billion and 251,770 causalities, in damages [7]. Moreover, the authors argue that the impact from this period has been 100 times higher than during the time period 1978–1997.

Following the 2004 tsunami in the Indian Ocean, there has been a large amount of literature published on several topics associated with tsunami science. For example, research has been conducted on the physics of tsunami waves [12], tsunami’s impact and characteristics [1, 2, 3, 11, 13], tsunami early warning systems [14, 15], tsunami risk assessment [8, 10, 11, 16], geology’s perspective [17, 18, 19], to mention a few.

Recent tsunamis have highlighted the need for an effective early warning system. An early warning is defined as “the provision of timely and effective information, through identified institutions, that allows individuals exposed to a hazard to take action to avoid or reduce their risk and prepare for effective response” [20]. Moreover, the United Nations Inter-Agency Secretariat of the International Strategy for Disaster Reduction (UN/ISDR) argues that an “effective early warning system” should include the following four key elements: “the knowledge of risks,” “the technical monitoring and warning service,” “dissemination & communication of meaningful warnings to those at risk,” and “the public awareness and preparedness to react to warnings” [20, 21].

The objective of the paper is to highlight the tsunami risk in Mexico. The data showed in the paper are based on previous studies on tsunamis in the country [15, 22]. Further, a preliminary “tsunami early warning” system which aims at integrating, for example, the four key elements proposed by the UNISDR [20] for the case of Mexico is presented.

2. The risk of tsunamis in Mexico

The “Pacific ring of fire” belt covers a vast area of highly active tectonic plate boundaries where most of the earthquakes originate and active volcanoes (Figure 1). It is believed that three quarters of all the volcanoes in the world are in the ring [23].

Moreover, the Ring of fire runs through several countries, such as Canada, USA, Russia, Chile, Peru, Guatemala, New Zealand, Japan, Indonesia, Philippines, and Mexico.

Regarding the tsunami risk in Mexico, studies based on tsunami historical data showed that there are two zones of tsunami threat: local (i.e., generation of tsunamis) and remote (i.e., arrival of tsunamis) (Figure 2) [15, 22]. The authors defined these two zones by considering the nature of the faulting and tectonic plate interaction. In the subsequent subsection, each of these will be addressed.

2.1 Local tsunami risk

According to [15, 22] at the west of the “Rivera plate” and along the “Middle America trench,” the “Cocos plate” subduction beneath the “North American plate” at rates of 2.5–7.7 cm/year (Figure 2). Given the fact, that large earthquakes occur in this region; therefore, the zone has been regarded as a generator of tsunamis (Table 1 and Figure 3).

Year	Region	Magnitude	Tsunami (places hit, Mexico)	Max. height waves (m)
1732	Guerrero	—	Acapulco	4.0
1754	Guerrero	—	Acapulco	5.0
1787	Guerrero	>8.0	Acapulco	3–8
1787	Oaxaca	—	Juquila Pochutla	4.0 4.0
1820	Guerrero	7.6	Acapulco	4.0
1852	B. C.	—	Río Colorado	3.0
1907	Guerrero	7.6	Acapulco	2.0
1925	Guerrero	7.0	Zihuatanejo	7.0–11.0
1932	Jalisco	8.2	Manzanillo San Pedrito	2.0 3.0
1932	Jalisco	7.8	Manzanillo	1.0
1932	Jalisco	6.9	Cuyutlán	9.0–10.0
1948	Nayarit	6.9	Islas Marias	2.0–5.0
1957	Guerrero	7.8	Acapulco	2.6
1973	Colima	7.6	Manzanillo	1.1
1978	Oaxaca	7.6	Puerto Escondido	1.5
1979	Guerrero		Acapulco	1.3
1985	Michoacán	8.1	Lázaro Cardenas Ixtapa Zihuatanejo Playa Azul Acapulco Manzanillo	2.5 3.0 2.5 1.1 1.0
1985	Michoacan	7.8	Acapulco Zihuatanejo	1.2 2.5
1995	Colima	8.1	Boca de Iguanas Barra de Navidad San Mateo Melaque Cuastecomate El Tecuán Punta Careyes Chamela Pérula Punta Chalacatepec	5.10 5.10 4.90 4.50 4.40 3.80 3.50 3.20 3.40 2.90
2003	Colima	7.8	Manzanillo	1.22
2017	Chiapas	8.1	Salina Cruz	1.10

Table 1.

Local tsunamis-only those with height >1.0 m is shown [22].

According to the historical data, the generated tsunamis that produced the highest wave heights were those that occurred in 1925 (7–11 m), 1932 (9–10 m), 1995 (2.9–5.10 m), and 1985 (1–3 m). For example, the 1985 earthquake of 8.1 Ms of magnitude generated a tsunami that affected several communities in this zone. It is believed that a key infrastructure port was affected with waves of 2.5 m and flooded the area about 500 m inland [15]. Also, several tourist resorts were affected by the tsunami; for example, waves for up to 2.5 m high were observed in Playa de Azul [15].

Interestingly, a day after the main earthquake, a 7.5 Ms aftershock hit the zone; it is thought the generated tsunami affected a local fishing community with waves ranging from 2 to 3 m high [15].

2.2 Remote tsunami risk

It is believed that on the Northwest of the “Rivera plate” (Figure 2), along the Gulf of California where the Pacific Plate slides north with respect to the North American plate, generation of tsunamis in this zone is unlikely [15, 22]. This is consistent with historical data (Table 2); it can be seen that data on “small” and “moderate” tsunamis generated by remote sources; for example, the two most recent 2010 Chile and the 2011 tsunamis (Figure 4) were the maximum wave heights registered were <1.0 m.

Date	Region	Magnitude	Tsunami (places hit, Mexico)	Max. height waves (m)
1952	Kamchatka, USSR	8.3	La Paz, BCS Salina Cruz	0.5 1.2
1957	Aleutian Islands	8.3	Ensenada, B.C.	1.0
1960	Chile	8.5	Ensenada, B.C. La Paz, B.C.S. Mazatlán Acapulco Salina Cruz	2.5 1.5 1.1 1.9 1.6
1960	Peru	6.8	Acapulco	0.10
1963	Kuril, Islands, USSR	8.1	Acapulco Salina Cruz Mazatlan La Paz, B.C.S.	<1.0
1964	Alaska	8.4	Ensenada, B.C. Manzanillo Acapulco Salina Cruz	2.4 1.2 1.1 0.8
1968	Japan	8.0	Ensenada, B.C. Manzanillo Acapulco	<1.0
1975	Hawaii	7.2	Ensenada, B.C. Manzanillo Puerto Vallarta Acapulco	<1.0
1976	Kermadec Islands	7.3	San Lucas, B.C.S. Puerto Vallarta Manzanillo Acapulco	<1.0
1995	Chile	7.8	Cabo San Lucas	<1.0
2004	Indonesia	9.0	Manzanillo Lazaro Cardenas Zihuatanejo	1.22 0.24 0.60
2010	Chile	8.8-9.0	Manzanillo Cabo San Lucas Acapulco	0.32 0.36 0.62
2011	Japan	9.0	Ensenada, B.C. Huatulco Puerto Angel Acapulco	0.70 0.70 0.29 0.72
2018	Indonesia	7.5	—	—
2018	Indonesia	AK Vulcano tsunami	—	—

Table 2.

Remote tsunamis-historical data taken from [22] with the exception of the last two tsunamis that occurred in 2018.

However, it is worth mentioning that the historical data showed that there were two tsunamis that registered the height of waves up to 2.4 and 2.5 m; that is, those generated in Chile (1960) and Alaska (1964), respectively (Table 2).

3. A Mexican tsunami early warning system

The previous section and the most recent tsunami events [2, 3, 4] have highlighted the need for an effective tsunami early warning system (TEWS). A system should include “tsunami early warning coordination centres (TEWCC)” covering the whole of the Pacific coast of Mexico. Moreover, the system should also include earthquake early warning (EEW) systems. Furthermore, these systems should be explicitly “people-centered” [21, 26]. However, only those aspects associated with the features of a TEWS will be discussed in some detail. The proposed model is based on previous research on issues related to safety and disaster management systems [27, 28, 29].

Figure 5 shows what is called a “structural organization” of the model, which comprises essentially a set of five highly interrelated subsystems (systems 1–5).

In the context of this case study, the overall function of systems 2–5 (MTEW-SMU) is to establish the key tsunami safety policies aiming at maintaining tsunami risk within an acceptable range; this implies allocating the necessary resources, for example, to build response capabilities at national and community levels. System 1, on the other hand, embraces the TNZO (Tsunami Northern Zone Operations) and TSZO (Tsunami Southern Zone Operations) with their associated management units (TNZ-SMU and TSZ-SMU). These two operations of system 1 were considered given the fact that the risk of tsunamis comes from local and remote tsunami sources as mentioned in Section 2. See Section 2.

It is important to highlight that one of the key functions within the MTEW-SMU is that related to system 2, which is associated with what it is called here MTEW-CC (Mexican Tsunami Early Warning Coordination Centre); its key function is the monitoring of the TSZ-CC (Tsunami Southern Zone-Coordination Centre) and TNZ-CC (Tsunami Northern Zone Coordination Centre), as shown in Figure 5. The process of the flow of key information and decision making is described in Table 3.

Following the 2004 tsunami in the Indian Ocean, the need for a tsunami warning system (TWS) was more than evident; however, it may be argued that the existing TWS may be deficient in dealing with the mitigation of impacts of such events; moreover, there are still regions worldwide without such systems (Table 4).

Recent tsunami disasters have highlighted some of these deficiencies; for example, in the case of the 2010 tsunami in Chile, the entity in charge of issuing a tsunami warning failed to do so [24] (see “action point” “2”and “7” in Figure 5and Table 3). The failure to perform this action contributed to fatalities in the coastal communities. More recently, the 28 September Sulawesi tsunami and the 24 December Anak Krakatau (AK) volcano tsunami, both in Indonesia, illustrate deficiencies in TWS too. In the former case, the tsunami warning was issued but the warning was lifted over 30 minutes [4]. However, the city of Palu, located in a narrow bay, was hit hard with waves reaching 6 m of height; why were not they warned? The head of the BMKG (Indonesia Agency for Meteorology, Climatology and Geophysics) argued that “we have no observation data at Palu…,” “If we had a tide gauge or proper data in Palu, of course it would have been better” [4]. The tsunami (and earthquake) killed over 2000 people [2]. Finally, regarding the AK volcano tsunami, it is thought that there was not a tsunami warning system for the case of volcano-induced tsunamis, the tsunami killed 437 people [3].

It may be argued that a TWS should not be only concerned with the technical aspects (e.g., tidal gauge, network of buoys, etc.), but also the organizational and human components. In other words, there is a need for an effective tsunami early warning system that is able to consider all these components in a coherent manner, such as the system being proposed in here and elsewhere. Moreover, these systems should be “people-centered” [21, 26].

4. Conclusions

This paper has presented the risk of tsunamis in Mexico. The approach has been a review of existing literature on historical data of tsunami occurrence in Mexico. The literature survey showed that the tsunami threat comes from local and remote zones. Overall, the review showed that the highest tsunami risk comes from tsunamis induced by earthquakes occurring in the Southern zone of the country (i.e., local zone). The paper has also put forward a preliminary model of a TEWS (Tsunami Early Warning System) for the case of Mexico. However, it needs further research to design the whole networks of the flows of information not only for the case of tsunamis, but also for the case of earthquake early warning system.

Acknowledgments

This research was supported by the following grants: CONACYT-No:248219; SIP-IPN-20201790.

Conflict of interest

The authors declare that they have no competing interests.