Stephanie Ross Soil characteristics of LUSI’s mud Feb 12 2008 p. 1 Soil Characteristics of Mud From the Indonesian Mud Volcano “LUSI” Stephanie Ross Abstract In Sidoarjo, on the island of Java, Indonesia, a mud volcano nicknamed “LUSI” has been erupting since May of 2006. Although belated efforts were made to contain the mudflow, a region greater than 600 hectares (Jakarta AFP 2008) has been completely inundated. The mud has become the new substrate of the region, so its fertility may influence species recolonization of the area as well as indicate the potential of future land-use. Since most mud volcanoes are studied for their fluid mosaics and gaseous effluxes, no studies have specifically investigated the mud for its nutritive qualities. This study establishes a simple fertility index of LUSI’s mud, by testing for three soil properties that are important for plant growth: Carbon to nitrogen ratio (C:N), pH and cation exchange capacity (CEC). LUSI’s C:N ratio (12.1 ± 1.01, n = 13) fell at the low end of the of corresponding tropical soil data range (10.3-27) (Trumbore 1993). LUSI’s pH was found to be basic (8.22 ± 0.062, n = 13) relative to the range of tropical soil pH (3.9-6.3) (Motavalli et al. 1995). LUSI’s CEC (19.72 cmol+/kg ± 1.28, n = 12) was high relative to tropical soil CEC (6.55 cmol+/kg ± 1.12, n = 9) (Trumbore 1993)More specifically, LUSI’s %C (1.293% C ± 0.0448, n = 13) and %N (0.1076% N ± 0.0052, n = 13) were both very low (Motavalli et al. 1995, Ewel et al. 1991). These values indicate that C and N may need to be fertilized for plant growth because levels are so minimal, and buffering for the basic pH may be necessary as well. The high CEC levels indicate there are reasonable amounts of nutrient cations present in the mud. Together these results indicate that although the mud is not completely infertile, but reutilization of the region for agricultural use will probably require a significant amount of modification to the mud.Stephanie Ross Soil characteristics of LUSI’s mud Feb 12 2008 p. 2 Introduction Unique among mud volcanoes is “LUSI”, which erupted May 29th 2006 in Sidoarjo, Java, Indonesia, close to heavily populated regions of the island (Davies et al. 2007). Still exuding mud, it is the largest and longest lasting of reported mud eruptions (Mazzini et al. 2007). Mud volcanoes usually subside in a few days or weeks (Mazzini et al. 2007), but LUSI has been erupting for almost 2 years. Before leveling to its current 130,000-150,000 m3/day (Jakarta AFP 2008), the flow rate peaked at 180,000 m3/day (Mazzini et al. 2007), an amount equal to 72 Olympic sized swimming pools. Moreover, the volume of this mud has an unusually high percentage of water (~70%), which makes it “an outlier at the dilute watery end of the [mud] volcanoes’ viscosity spectrum” (Cyranoski et al. 2007). An expected percentage would be approximately 20-40% water (Hovland et al. 1997) given its depth of eruption estimated to be between ~1615-1828m (Mazzini et al. 2007). Furthermore, there is heavy subterranean pressure buildup; therefore, the core eruption column has not clogged allowing for continued mud expulsion (Cyranoski et al. 2007). The magnitude and length of the eruption has been so great that mud and water have inundated an area of approximately 600 hectares, an area equal to 2200 football fields (Jakarta AFP 2008), and has displaced over 30,000 people (Mazzini et al. 2007). This is significant considering only 900 of the 1700 known mud volcanoes are terrestrial (Jerosch et al. 2007) and none of comparable scale has been documented before (Davies et al. 2007). Most mud volcanoes are studied during periods of dormancy after they have already been established (Mazzini et al. 2007), whereas LUSI has been monitored since its origin as a “pioneer mud volcano” (Davies and Stewart 2005). Interestingly, this has lead to a heated political and scientific debate as to whether the eruption was catalyzed by drilling operations (Cyranoski et al. 2007, Davies et al. 2007) or by a recent 6.3 magnitude earthquake (Mazzini et al. 2007). Aside from its unclear origins, LUSI does not categorize well into the three typical mudflow types (Lokbatan, Chikishlyar, and Schugin) as described by Dimitrov (2002, taken from Kalinko, 1964), which are summarized as follows: Lokbatan type: explosive with flames from ignited gasses and long periods of dormancy, well formed cones with high water content; Chikishlyar type: weak continuous eruption that lacks explosiveness, many vents emitting gasses and mud, pool-like, or only very slightly conic; Schugin type: represents the transitional type of mud volcano, weak activity during the periods of eruption, predominantly composite craters,Stephanie Ross Soil characteristics of LUSI’s mud Feb 12 2008 p. 3 presumably with minimal mudflow. Comparing these characteristics to LUSI’s makes it clear that LUSI does not fit in with any of these three classifications. Like the Lokbatan type, LUSI has high water content, but LUSI has had no long periods of dormancy, nor is LUSI conic in shape. Although LUSI is flat and not conic in shape, unlike the Chikishlyar type LUSI is not represented by weak activity, nor does it have more than one distinguishable epicenter. LUSI has least in common with the Schugin type, with neither weak activity, nor minimal mudflow. Since LUSI does not categorize well into the three established mud volcano types, it is plausible that its mud characteristics are also anomalous relative to other mud volcanoes. Numerous other mud volcanoes have been studied at the Alaskan Mountains (Sorey et al. 2005), Azerbaijan (Gallagher 2003), the Gulf of Cadiz (Hensen et al. 2007), Mt.Etna (Giammanco et al. 2007) etc. Usually such studies test or monitor gaseous effluxes (Giammanco et al. 2007) and fluid mosaics (Hensen et al. 2007), which refers to the variety of fluids (oil, brine, etc.) that may be present in the mud, and their possible origins from underground. Despite being new, even LUSI has had its gas and water composition extensively analyzed by Mazzini and colleagues (2007), but LUSI’s mud composition has not yet been investigated other than for the purpose of determining the depth of its epicenter (Mazzini et al. 2007). Some trends do emerge from studies of other mud volcanoes that could be seen in LUSI’s mud composition such as a basic pH of the mud (Ginsburg
View Full Document
Unlocking...