Disaster Mitigation Snake and Ladder Game to Improve Earthquake Disaster Preparedness (A Case Study: Yogyakarta 5 Senior High School)

Tectonic earthquakes are natural disasters that are difficult to predict when they occurs, therefore preparedness is needed to deal with them. This study aims to determine the improvement in student preparedness for tectonic earthquakes using Guncang Bumi snake and ladder learning media. This research is research and development using the ADDIE model (analysis, design, development, implementation, evaluation). The research subjects were 63 students of class XI of Science. Data collection techniques used were test questions. The data analysis technique used is descriptive analysis and independent t-test analysis. Based on the independent t-test analysis obtained sig <0,05, it can be concluded that there is a difference in preparedness between the experimental class and the control class. Based on the calculation of the improvement in preparedness score, the percentage of improvement in disaster preparedness for the experimental class is 67,65%. The improvement percentage in preparedness for the control class was 32,35%. Both classes have improved but the improvement over much experimental class. Therefore it can be concluded that the use of the Guncang Bumi snake and ladder can improve preparedness for a tectonic earthquake disaster.

Liquefaction in Palu: the cause of massive mudflows

The 7.5 Mw tectonic earthquake that hit Palu City on 28 September 2018 was followed by tsunami and liquefaction, triggered massive mudflows in Balaroa, Petobo, and Jono Oge areas. This study focuses on the generating factors of liquefaction such as the condition of soil lithology, depth of water table, the distance to the focal mechanism, and the thickness of soft sediment. Microtremor data, including the Horizontal Vertical Spectral Ratio (HVSR), geological condition, and borehole data, were examined to conduct the liquefaction analysis. The analysis results based on the microtremor data showed that the distribution of ground shear strain values in Palu City ranged from 0.75 × 10–4 to 2.56 × 10–4. The distribution of the locations of the liquefaction was correlated to the distribution of ground shear strain values. High ground shear strain values and a shallow groundwater level were discovered in Palu City valley, which indicates that liquefaction in Palu City will undoubtedly occur. The semi-empirical method confirmed that Balaroa, Petobo, and Jono Oge had undergone large-scale liquefaction at a maximum depth of 16 m below the ground level. The average peak of water runoff that generated the mudflow was estimated to be at 11.31 cm3/s. Since the soil has loose soil grain with high water content, the soil will turn into a massive amount of mud during the liquefaction.

Campi Flegrei, Vesuvius and Ischia Seismicity in the Context of the Neapolitan Volcanic Area

Studying seismicity in a volcanic environment provides important information on the state of activity of volcanoes. The seismicity of the Neapolitan volcanoes, Campi Flegrei, Vesuvius, and Ischia, shows distinctive characteristics for each volcano, covering a wide range of patterns and types. In this study we relocated some significant volcano-tectonic earthquake swarms that occurred in Campi Flegrei and Vesuvius. Moreover, we compared the earthquake occurrence evolution, the magnitude and the seismic energy release of the three volcanoes. Also, we considered the results of seismic analysis in the light of geochemical and ground deformation data that contribute to defining the state of activity of volcanoes. In Campi Flegrei, which is experiencing a long term unrest, we identified a seismogenic structure at shallow depth in Pisciarelli zone that has been activated repeatedly. The increasing seismicity accompanies an escalation of the hydrothermal activity and a ground uplift phase. At Vesuvius a very shallow seismicity is recorded, which in recent years has shown an increase in terms of the number of events per year. Earthquakes are usually located right beneath the crater axis. They are concentrated in a volume affected by the hydrothermal system. Finally, Ischia generally shows a low level of seismicity, however, in Casamicciola area events with a moderate magnitude can occur and these are potentially capable of causing severe damage to the town and population, due to their small hypocentral depth (typically &lt; 2.5 km). After the seismic crisis of August 21, 2017 (mainshock magnitude M = 4), the seismicity returned to a low level in terms of occurrence rate and magnitude of earthquakes. The seismicity of these three different volcanic areas shows some common aspects that highlight a relevant role of hydrothermal processes in the seismogenesis of volcanic areas. However, while the main swarms in Campi Flegrei and most of the Vesuvian earthquakes are distributed along conduit-like structures, the seismicity of Ischia is mainly located along faults. Furthermore, the temporal evolution of seismicity in Neapolitan volcanic area suggests a concomitant increase in the occurrence of earthquakes both in Campi Flegrei and Vesuvius in recent years.

Thermal remote sensing reveals communication between volcanoes of the Klyuchevskoy Volcanic Group

Volcanoes are traditionally considered isolated with an activity that is mostly independent of the surrounding, with few eruptions only (< 2%) associated with a tectonic earthquake trigger. Evidence is now increasing that volcanoes forming clusters of eruptive centers may simultaneously erupt, show unrest, or even shut-down activity. Using infrared satellite data, we detail 20 years of eruptive activity (2000–2020) at Klyuchevskoy, Bezymianny, and Tolbachik, the three active volcanoes of the Klyuchevskoy Volcanic Group (KVG), Kamchatka. We show that the neighboring volcanoes exhibit multiple and reciprocal interactions on different timescales that unravel the magmatic system’s complexity below the KVG. Klyuchevskoy and Bezymianny volcanoes show correlated activity with time-predictable and quasiperiodic behaviors, respectively. This is consistent with magma accumulation and discharge dynamics at both volcanoes, typical of steady-state volcanism. However, Tolbachik volcano can interrupt this steady-state regime and modify the magma output rate of its neighbors for several years. We suggest that below the KVG the transfer of magma at crustal level is modulated by the presence of three distinct but hydraulically connected plumbing systems. Similar complex interactions may occur at other volcanic groups and must be considered to evaluate the hazard of grouped volcanoes.

Slowly migrating tectonic microearthquake swarms in the Icelandic Rift Zone: driven by pore-pressure or aseismic slip transients?

&lt;p&gt;Intense swarms of microearthquakes have been detected in the rift zone of Central Iceland since the 1970s, but the cause of their clear swarm-like nature remains enigmatic. We use the QuakeMigrate earthquake detection and location software&lt;sup&gt;1&lt;/sup&gt; to produce a highly complete catalogue of microseismicity from 2007-2020, using data from a dense local seismic network. Automatic hypocentre locations have been refined using waveform cross-correlation and double-difference relocation, and tightly constrained focal mechanisms have been obtained by manual analysis of a subset of events.&lt;/p&gt;&lt;p&gt;The resulting high-resolution earthquake catalogue reveals a network of conjugate strike-slip faults, oriented to accommodate plate-boundary extension. Sharply defined fault planes imaged by the microearthquake hypocentres range from 1-10 km in length, and are found between 1 and 8 km b.s.l., with their orientations closely matching the fault plane geometry inferred from the fault plane solutions. Seismicity within individual swarms displays a systematic migration of hypocentres at velocities of ~ 1 km/day. In the majority of swarms we also observe clusters of identical repeating events, providing evidence for re-loading of brittle asperities.&lt;/p&gt;&lt;p&gt;For a selection of swarms our high resolution seismic observations are complemented by GPS and InSAR measurements, allowing us to place constraints on the amount of fault slip. Comparing this, and the area of the fault plane activated in the swarm, to the seismic moment release reveals a significant contribution of aseismic slip, or very low effective stress drop. Analysis of swarms within this fault network triggered by the 2014 B&amp;#225;r&amp;#240;arbunga-Holuhraun dike intrusion provides further constraint on the amplitude of the stress cycle.&lt;/p&gt;&lt;p&gt;We combine our observations with comparisons to numerical &amp; laboratory modelling studies, observed swarm scaling properties and knowledge of the geological and permeability structure of the Icelandic crust to determine the nature of the transient forcing driving these exceptionally well-recorded tectonic earthquake swarms.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;1: https://github.com/QuakeMigrate/QuakeMigrate Tom Winder, Conor Bacon, Jonathan D. Smith, Thomas S. Hudson, Julian Drew, &amp; Robert S. White. (2021, January 15). QuakeMigrate v1.0.0 (Version v1.0.0). Zenodo. http://doi.org/10.5281/zenodo.4442749&lt;/p&gt;

Time Evolution of Tectonic Earthquake in Ambon, Indonesia

The advancement of earthquake seismology brings a new insight into earthquake detection. Advanced signal processing by implementing sliding-window mathematical techniques of cross-correlation into data stream are able to recognize low amplitude earthquake signals even under the presence of noise. Clear detection of the onset of low amplitude seismic waves is crucial, however they often hidden by larger amplitudes of coda waves after the generation of mainshock event. By performing template matching algorithm we found a detail temporal variation of seismicity related to Mw 6.6 Ambon earthquake. In comparison, the detection level is up to eight times from conventional method. The method also reveals a seismic migration before the main event coincide with the direction of local tectonic movement derived from previous GPS analysis. Since the method able to detect the earthquake within their family, it gives a reasonably significant improvement to virtual stress-meter analysis. Highly accumulated stress preceding the main event depicted by b-value drop are clearly mapped in a high confidence level.

Liquefaction in Palu: The Cause of Massive Mudflows

The 7.5 Mw tectonic earthquake that hit Palu City on 28 September 2018 was followed by tsunami and liquefaction that triggered massive mudflows in Balaroa, Petobo, and Jono Oge areas. Extensive damages to infrastructures occurred as the result of these earthquake-triggered disasters. This study explores the causing factors of the massive mudflow in Balaroa, Petobo, and Jono Oge areas as it is a quite rare phenomenon. This study focuses on the causing factors of liquefaction such as the condition of soil lithology, depth of water table, distance to the fo[1]cal mechanism, and the thickness of soft sediment. To carry out the liquefaction analysis, important data, such as microtremor data which included the Horizontal Vertical Spectral Ratio (HVSR), geological condition, and borehole data, were examines. Additional data i.e. ground layers slopes and other factors were also investigated. Normally, these data are not considered when observing common liquefaction. However, for the case of massive mudflows in Balaroa, Petobo, and Jono Oge, they become the key factors. Based on the microtremor data, the analysis results show that the distribution of ground shear strain values in Palu City ranges from 0.75×10-4 to 2.56×10-4. The distribution of the locations of the liquefaction corresponds to the distribution of ground shear strain values. High ground shear strain values were discovered in Palu City valley. Such high value and groundwater level indicate that liquefaction in Palu City will certainly take place. The semi-empirical method confirms that Balaroa, Petobo, and Jono Oge have high potential for large-scale liquefaction to occur at a maximum depth of 16 meters below the ground surface. Having loose soil grain with high water content, the soil will turn into a massive amount of mud during the liquefaction. In addition, ground slopes and ground vibration due to the earthquake will create massive mudflows similar to flash flood. However, the mudflows movement is slow since the slope inclination is slight.

Analysis of Padang City community preparedness to face the earthquake and tsunami disaster

Padang, West Sumatra is located in the collision area of two tectonic plates, namely Indo-Australia and Eurasia. Which is marked by the presence of a tectonic earthquake center in the Mentawai islands and surroundings. Realising the high risk of disasters, the people of Padang city must be ready and prepared for the possibility of an earthquake and tsunami. To reduce the risk of disaster, the use of “self-help” and “mutual-help” parameter might be the best way to help the people to know “what should they do?” and “how can they do it?” to protect themselves from disasters. This research aims to analyse the Padang city community’s preparedness to face the Earthquake and Tsunami disaster by using “self-help” and “mutual-help” parameters. A questionnaire consisting of 20 questions was used to collect the data. The sample size of this research is 400. The data was collected from 4 different areas (Random area, Pondok area, Purus area, and Ulak Karang area). The study found that the Padang city community might not be prepared to face the earthquake and tsunami disaster in the future in terms of self-help and mutual help as most of the items mentioned in the questionnaire have not been applied. The government is urged to develop appropriate policies regarding further disaster risk reduction